<PAGE>   1

                                            ***TEXT OMITTED AND FILED SEPARATELY
                                                CONFIDENTIAL TREATMENT REQUESTED
                                          UNDER 17 C.F.R. SECTIONS 200.80(b)(4),
                                                            200.83 AND 240.24b-2
                                                           Agreement No. 99-0027

                                LICENSE AGREEMENT

        This Agreement is made effective the 23rd day of April, 1999, by and
between Wisconsin Alumni Research Foundation (hereinafter called "WARF"), a
nonstock, nonprofit Wisconsin corporation, and Geron Corporation (hereinafter
called "Geron"), a corporation organized and existing under the laws of
Delaware;

        WHEREAS, WARF owns certain inventions that are described in the
"Licensed Patents" defined below;

        WHEREAS, WARF and Geron had previously entered into a license agreement,
Agreement No. 95-0208 dated January 1, 1996, as amended on March 19, 1997 and
March 1, 1998, (the "Previous License");

        WHEREAS, WARF and Geron desire to enter into this Agreement to clarify
and refine the agreement between the parties; and

        WHEREAS, WARF and Geron agree that this Agreement shall supersede the
Previous License in its entirety.

        NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth below, the parties covenant and agree as follows:

        Section 1. Definitions.

        For the purpose of this Agreement, the Appendix A definitions shall
apply.

        Section 2. Grant.

                A. License.

                        (i) WARF hereby grants to Geron an exclusive license,
limited to the Licensed Field and the Licensed Territory, under the Licensed
Patents to make, have made, develop, have developed, use, sell, offer for sale,
and import Products.

                        (ii) WARF hereby grants to Geron an exclusive license,
limited to the Licensed Field and the Licensed Territory, under the Licensed
Patents to make, have made, develop, have developed, use, sell, offer for sale,
and import Research Products.

                        (iii) WARF hereby grants to Geron a nonexclusive
license, limited to the Licensed Territory, to use the Licensed Patents for
internal research purposes. In the event that Geron identifies a research
collaborator that Geron desires to obtain Materials for research purposes, Geron
shall submit a written request to WARF asking that WARF arrange to transfer
Materials to such research collaborator. WARF shall then enter into negotiations
directly with such research collaborator using its standard Materials Transfer
Agreement for the Materials and shall arrange for transfer of the Materials
thereunder.


<PAGE>   2

                B. Sublicenses.

                        (i) Geron may grant written sublicenses to third parties
under the exclusive licenses granted herein. Any agreement granting a sublicense
shall state that the sublicense is subject to the termination of this Agreement.
Geron shall require that its sublicensee(s) comply with all requirements of this
Agreement and Geron shall have the same responsibility for the activities of any
sublicensee as if the activities were directly those of Geron.

                        (ii) In respect to sublicenses granted by Geron under
this Section 2B, Geron shall pay to WARF an amount equal to what Geron would
have been required to pay to WARF had Geron sold the amount of Products sold by
such sublicensee. In addition, if Geron receives any fees, minimum royalties, or
other payments in consideration for any rights granted under a sublicense,
except for payments received by Geron upon achievement of the milestones set
forth in Section 4E (provided that Geron makes payment to WARF upon achievement
of such milestones pursuant to Section 4E), and such payments are not based
directly upon the amount or value of Products sold by the sublicensee, then
Geron shall pay WARF [...***...] percent ([...***...]%) of such payments in
the manner specified in Section 4F. WARF recognizes that dollars received from
sublicensees to fund research are not consideration for rights granted under the
sublicense and as such research funds are not subject to sharing with WARF
hereunder. However, Geron shall not receive from sublicensees anything of value
in lieu of cash payments in consideration for any sublicense under this
Agreement without the express prior written permission of WARF. Both parties
agree to act in good faith when negotiating the consideration to be paid for
sublicensing and when assessing whether such consideration is subject to sharing
with WARF under this Section 2B(ii).

                C. First Option to Negotiate.

        WARF hereby grants Geron the first option to negotiate an exclusive
license for addition of cell types to the Licensed Field. Geron may exercise its
option under this Section 2C by providing WARF with written notice of its desire
to add a cell type to the License Field including a Development Plan detailing
Geron's plan and timeline for bringing Products to market incorporating the new
cell type and by paying WARF an upfront license fee to be negotiated in good
faith between the parties factoring in commercially reasonable terms given the
advancement of cell therapy in therapeutics and diagnostics and the value added
by Geron. The terms of the exclusive license, other than the upfront license
fee, shall be identical to the terms set forth in this Agreement, unless
otherwise negotiated and agreed to by the parties. If the parties fail to agree
on an upfront license fee for an additional cell type, WARF agrees that it will
not offer such cell type to any third party on terms more favorable as a whole
to such licensee than were offered to Geron hereunder for a period of
[...***...] ([...***...]) months from the date Geron first exercised its option
to add a cell type to the Licensed Field. In the context of this Agreement,
"terms more favorable as a whole" shall mean that the combination of the
commercial terms, for example the license fee, royalty rate, milestones, minimum
royalties, and other fees required as consideration for the rights granted under
the license are not more favorable when taken together than the package offered
to Geron. The option to add cell types shall expire on [...***...] unless
extended for an additional period by written agreement on terms mutually
agreeable to the parties.

                D. License to WARF.

        To the extent permitted by applicable law, Geron hereby grants WARF (and
to the University of Wisconsin - Madison) a nonexclusive, royalty-free, paid-up
research license under any and all inventions hereafter made or acquired by
Geron to the extent any such inventions are Improvements. Such license

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TREATMENT AND HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
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                                  Page 2 of 17
<PAGE>   3

shall be nontransferable as long as Geron remains an existing and solvent entity
but may be transferable upon bankruptcy or dissolution of Geron other than in
the event of the sale of substantially all of Geron's assets pursuant to Section
8. "Improvements" shall mean any modification of an invention described in
Licensed Patents which, if unlicensed, would infringe one or more claims of the
Licensed Patents. Geron shall provide WARF with a written, enabling disclosure
of each such invention (such as a U.S. patent application), unambiguously
identifying it as an invention governed by this paragraph, within six (6) months
of filing a patent application thereon.

        Section 3. Development Plans and Reporting

        Geron must provide WARF with a broad development plan (see Appendix E)
outlining its general plan and timeline for developing Products in the Licensed
Field. In addition, Geron shall provide WARF with a specific development plan,
acceptable to WARF, including key milestones dates for submission of IND or
comparable filing to the United States Food and Drug Administration or its
foreign equivalent, date of NDA approval or comparable approval, and the
projected date of first commercial sale for Products related to each cell type
in the Licensed Field. Geron shall provide the development plan to WARF upon
execution of this Agreement. Furthermore, Geron agrees to and warrants that: it
has, or will obtain, the expertise necessary to independently evaluate the
inventions of the Licensed Patents; it will establish and actively and
diligently pursue the development plan to the end that the inventions of the
Licensed Patents will be utilized to provide Products for sale. Within one month
following the end of each calendar quarter ending on March 31, June 30,
September 30 and December 31 and until commercial sales of Products begin, Geron
will supply WARF with a written Development Report showing Geron's progress
toward bringing Products to market in the Licensed Field. All development
activities and strategies and all aspects of Product design and decisions to
market and the like are entirely at the discretion of Geron, and Geron shall
rely entirely on its own expertise with respect thereto. WARF's review of
Geron's development plan and Development Reports shall be considered
confidential information subject to the obligations set forth in Section 19
hereto and shall be solely to verify the existence of Geron's commitment to
development activity and to assure compliance with Geron's obligations to
utilize the inventions of the Licensed Patents to make Products available for
sale in the marketplace, as set forth above. WARF may within thirty (30) days of
its request, review all documentation and records relating to Geron's
development of the cell lines. Geron shall make such records available at a
single United States location. Such review may be performed by any employee of
WARF, or any agent designated by WARF. The parties recognize that the
development plans are likely to change as Geron's research and development of
Products advances; therefore, the parties agree to negotiate in good faith with
regard to any revisions to the development plans submitted to WARF. Failure to
meet key milestones for development of Products set forth in the development
plan shall be subject to review by WARF and may result in termination of the
license under Section 7D for any cell types Geron cannot demonstrate diligence
and commitment to developing.

        Section 4. Consideration.

                A. License Fee.

        Geron agrees to pay to WARF a license fee comprised of $[...***...]
cash; 100,000 options, granted pursuant to Geron's 1994 Stock Option Plan, a
copy of which is attached hereto as Appendix F; provided that such options shall
have an exercise period of ten years and that the strike price of said options
shall be equal to the closing price of Geron stock as of the day prior to the
effective date of this Agreement; and 20,000 shares of common stock within
thirty (30) days after executing this Agreement as consideration for the
exclusive rights granted in the Licensed Field hereunder. In the event that WARF
is determined to be ineligible to participate in Geron's 1994 Stock Option Plan
by a governmental agency or

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                                  Page 3 of 17
<PAGE>   4

body, Geron agrees to replace such options with Shares of Geron's common stock
having the equivalent value of the options issued to WARF within thirty (30)
days of such determination. The value of the options shall be as of the date of
issuance to WARF hereunder using the Black-Scholes Model for valuation of such
options.

                B. Extension of Patent Term.

        Geron and WARF hereby agree that they will make all necessary filings
and provide all necessary documentation to allow WARF to apply for an extension
of the patent term for each of the Licensed Patents pursuant to 37 CFR 1.710 et
seq.

                C. Filing of Foreign Applications.

                        (i) Geron agrees to pay to WARF patent reimbursement to
reimburse WARF for a portion of the costs associated with filing, prosecuting
and maintaining the Licensed Patents. Geron has paid some patent reimbursement
under the terms of the Previous License. However, Geron agrees to pay to WARF
patent reimbursement of $[...***...] per United States patent application within
thirty (30) days of adding a patent to Licensed Patents hereunder. In addition,
Geron shall notify WARF of which countries outside the United States Geron
desires foreign patent protection and Geron shall pay to WARF patent
reimbursement of $[...***...] per PCT application and $[...***...] per patent
application per country outside the United States upon nationalization from the
PCT application. WARF reserves the right to file and maintain foreign patent
applications in jurisdictions outside those requested by Geron at its own
expense; however, for any jurisdiction in which WARF files patent applications
without patent reimbursement from Geron, the exclusive license granted to Geron
under this Agreement shall be converted into a nonexclusive license subject to
all the terms of this Agreement.

                        (ii) WARF will prosecute all applications until WARF
determines that continued prosecution is unlikely to result in the issuance of a
patent in that country. WARF will timely provide copies of all patent
communications with the US Patent Office or its foreign counterpart to Geron and
allow Geron the opportunity to comment on the prosecution of the Licensed
Patents and patent applications. However, if WARF decides to abandon prosecution
of the application in a particular country, Geron shall be given notification
that WARF is terminating prosecution in that country. If Geron desires to
acquire rights in the application then WARF will cooperate with Geron as
reasonably requested by Geron to facilitate acquisition of such rights.

                D. Royalty.

                        (i) Geron agrees to pay to WARF as "earned royalties" a
royalty calculated as a percentage of the Selling Price of Products in
accordance with the terms and conditions of this Agreement. The royalty is
deemed earned as of the earlier of the date the Product is actually sold and
paid for, the date an invoice is sent by Geron, or the date a Product is
transferred to a third party for any promotional reasons. The royalty shall
remain fixed while this Agreement is in effect at a rate of [...***...] percent
([...***...]%) of the Selling Price for Therapeutic Products and [...***...]
percent ([...***...]%) of the Selling Price for Diagnostic Products and Research
Products.

                        (ii) If Geron must make payments to one or more third
parties during any calendar year to obtain a license or similar right in the
absence of which Geron could not legally make, use or sell the Products or
Research Products, then Geron may deduct [...***...] percent ([...***...]%) of
such third party payments from royalties payable to WARF with respect to that
calendar year, provided that such deduction

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                                  Page 4 of 17
<PAGE>   5

does not exceed [...***...] percent ([...***...]%) of the royalties payable to
WARF under this Agreement during such calendar year.

                E. Minimum Royalty and Milestone Payment.

                        (i) Geron agrees to pay to WARF a minimum royalty per
calendar year or part thereof during which this Agreement is in effect starting
in calendar year 2003, against which any earned royalty paid for the same
calendar year will be credited. The minimum royalty shall be $[...***...] in
2003, $[...***...] in 2004, $[...***...] in 2005 and in each calendar year
thereafter. The minimum royalty payment for a given year shall be due at the
time payments are due for the calendar quarter ending on December 31. It is
understood that the minimum royalties will apply on a calendar year basis, and
that sales of Products requiring the payment of earned royalties made during a
prior or subsequent calendar year shall have no effect on the annual minimum
royalty due WARF for any given calendar year.

                        (ii) Geron further agrees to pay to WARF milestone
payments as outlined below within thirty (30) days from the specified event set
forth below whether achieved by Geron or its sublicensee(s). These payments are
not creditable against running royalties or other payments due hereunder.

<TABLE>
<CAPTION>
EVENT                                                  CASH              OPTIONS                         SHARES
<S>                                                    <C>               <C>                             <C>
---------------------------------------------------    --------------    ---------------------------     ------------------
IND or comparable regulatory filing for the first      $[...***...]      50,000 options pursuant to      5,000 shares of
Product developed from each cell type                                    the 1994 Stock Option Plan      Geron Common Stock
---------------------------------------------------    --------------    ---------------------------     ------------------
NDA or comparable regulatory approval for the first    $[...***...]      100,000 options pursuant to     10,000 shares of
Product developed from each cell type                                    the 1994 Stock Option Plan      Geron Common Stock
---------------------------------------------------   --------------    ----------------------------     ------------------
</TABLE>

                F. Accounting; Payments.

                        (i) Amounts owing to WARF under Sections 2B and 4D shall
be paid on a quarterly basis, with such amounts due and received by WARF on or
before the forty-fifth (45th) day following the end of the calendar quarter
ending on March 31, June 30, September 30 or December 31 in which such amounts
were earned. The balance of any amounts which remain unpaid more than thirty
(30) days after they are due to WARF shall accrue interest until paid at the
rate of the lesser of [...***...] percent ([...***...]%) per month or the
maximum amount allowed under applicable law. However, in no event shall this
interest provision be construed as a grant of permission for any payment delays.

                        (ii) Except as otherwise directed, all amounts owing to
WARF under this Agreement shall be paid in U.S. dollars to WARF at the address
provided in Section 16(a). All royalties owing with respect to Selling Prices
stated in currencies other than U.S. dollars shall be converted at the rate
shown in the Federal Reserve Noon Valuation - Value of Foreign Currencies on the
day preceding the payment.

                        (iii) A full accounting showing how any amounts owing to
WARF under Sections 2B and 4D have been calculated shall be submitted to WARF on
the date of each such payment. Such accounting shall be on a per-country and
product line, model or tradename basis and shall be summarized on the form shown
in Appendix C of this Agreement. In the event no payment is owed to WARF, a
statement setting forth that fact shall be supplied to WARF.

        Section 5. Certain Warranties of WARF.

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                                  Page 5 of 17
<PAGE>   6

                A. WARF warrants that except as otherwise provided under Section
14 of this Agreement with respect to U.S. Government interests, it is the owner
of the Licensed Patents or otherwise has the right to grant the licenses granted
to Geron in this Agreement. However, nothing in this Agreement shall be
construed as:

                        (i) a warranty or representation by WARF as to the
validity or scope of any of Licensed Patents;

                        (ii) a warranty or representation that anything made,
used, sold or otherwise disposed of under the license granted in this Agreement
will or will not infringe patents of third parties; or

                        (iii) an obligation to furnish any know-how not provided
in Licensed Patents or any services other than those specified in this
Agreement.

                B. WARF MAKES NO REPRESENTATIONS, EXTENDS NO WARRANTIES OF ANY
KIND, EITHER EXPRESS OR IMPLIED, AND ASSUMES NO RESPONSIBILITIES WHATSOEVER WITH
RESPECT TO USE, SALE, OR OTHER DISPOSITION BY GERON OR ITS VENDEES OR OTHER
TRANSFEREES OF PRODUCTS INCORPORATING OR MADE BY USE OF INVENTIONS LICENSED
UNDER THIS AGREEMENT.

        Section 6. Recordkeeping.

                A. Beginning when the first of the Products is sold, Geron and
its sublicensee(s) shall keep books and records sufficient to verify the
accuracy and completeness of Geron's and its sublicensee(s)'s accounting
referred to above, including without limitation inventory, purchase and invoice
records relating to the Products or their manufacture. Such books and records
shall be preserved for a period not less than six years after they are created
during and after the term of this Agreement; however, WARF shall have the right
to audit the most recent three (3) years of books and records. If a discrepancy
of five percent (5%) or more of the royalties paid in any given year is found,
WARF shall have the right to audit an additional three (3) years of books and
records.

                B. Geron and its sublicensee(s) shall take all steps necessary
so that WARF may within thirty (30) days of its request review and copy all the
books and records at a single U.S. location to verify the accuracy of Geron's
and its sublicensee(s)'s accounting. Such review may be performed no more than
annually by any independent attorney or registered CPA designated by WARF, upon
reasonable notice and during regular business hours.

                C. If a royalty payment deficiency is determined, Geron and its
sublicensee(s) shall pay the royalty deficiency outstanding within thirty (30)
days of receiving written notice thereof, plus interest on outstanding amounts
as described in Section 4F(i).

                D. If a royalty payment deficiency for a calendar year exceeds
five percent (5%) of the royalties paid for that year, then Geron or its
sublicensee shall be responsible for paying WARF's out-of-pocket expenses
incurred with respect to such review.


                                  Page 6 of 17
<PAGE>   7

        Section 7. Term and Termination.

                A. The term of this license shall begin on the effective date of
this Agreement and continue until the earlier of the date that no Licensed
Patent remains an enforceable patent or the payment of earned royalties under
Section 4D, once begun, ceases for more than [...***...] ([...***...])
consecutive calendar quarters.

                B. Geron may terminate this Agreement at any time by giving at
least ninety (90) days' written and unambiguous notice of such termination to
WARF. Such a notice shall be accompanied by a statement of the reasons for
termination.

                C. If Geron at any time defaults in the timely payment of any
monies due to WARF or the timely submission to WARF of any Development Report,
fails to actively pursue the development plan, or commits any breach of any
other covenant herein contained, and Geron fails to remedy any such breach or
default within ninety (90) days after written notice thereof by WARF, WARF may,
at its option, terminate this Agreement by giving notice of termination to
Geron.

                D. WARF may terminate this Agreement with respect to any
particular cell type for failure by Geron to meet milestones set forth in
Geron's development plan with respect to such cell type. In such event, WARF
shall provide Geron with notice of termination as a result of such default and
Geron shall have ninety (90) days to cure such default or provide WARF with a
revision acceptable to WARF of such development plan.

                E. Upon the termination of this Agreement, Geron shall remain
obligated to provide an accounting for and to pay royalties earned up to the
date of the termination and any minimum royalties shall be prorated as of the
date of termination by the number of days elapsed in the applicable calendar
year.

        Section 8. Assignability.

        This Agreement may not be transferred or assigned by Geron except to a
company in which Geron owns at least fifty percent (50%) of the equity; upon
sale or transfer of substantially all the assets of Geron or with the prior
written consent of WARF.

        Section 9. Enforcement.

        WARF intends to protect the Licensed Patents against infringers or
otherwise act to eliminate infringement, when, in WARF's sole judgment, such
action may be reasonably necessary, proper, and justified. In the event that
Geron believes there is infringement of any Licensed Patent under this Agreement
which is to Geron's substantial detriment, Geron shall provide WARF with written
notice that such infringement is occurring including reasonable evidence of the
infringement. In the event that WARF does take action to abate the infringement,
it shall do so at its own expense. Upon request by WARF, Geron shall take
action, join in an action, and otherwise provide WARF with such assistance and
information as may be useful to WARF in connection with WARF's taking such
action (if the cause of action arose during the term of this Agreement and WARF
reimburses Geron for Geron's reasonable out-of-pocket expenses upon recovery of
damages as described in this Section 9). Geron shall provide WARF with
assistance and shall have a right to review and comment on WARF's enforcement of
the Licensed Patents in the Licensed Field including the right to review any
proposed settlement of an infringement action prior to WARF's entering into such
an agreement. Any recovery or damages for

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COMMISSION.


                                  Page 7 of 17
<PAGE>   8

infringement derived through WARF taking such action shall be applied as
follows: (a) first, to WARF to reimburse WARF for the expenses of the
litigation, including reasonable attorneys' fees, (b) second, to Geron to
reimburse Geron for its reasonable expenses in assisting with such litigation,
including reasonable attorneys' fees, and (c) the balance of any recovery or
damages, except enhanced damages, shall be divided [...***...] ([...***...])
to Geron and [...***...] ([...***...]) to WARF. If WARF does not take action to
abate the infringement of the Licensed Patents within three (3) months of
receiving the notice described above, Geron may either reduce the royalty owed
on sales of Products under Section 3C in the country where the infringement is
occurring by [...***...] percent ([...***...]%) until such infringement is
abated or Geron may, with WARF's written consent, bring an action to enforce the
Licensed Patents. If Geron receives notice that it is being made a party to a
lawsuit and the Licensed Patents are implicated, then WARF shall take action
within a reasonable period to allow Geron to defend its interests and the
Licensed Patents. If Geron chooses to bring an action against the infringer of
the Licensed Patents, it shall do so at its own expense. Any recovery or damages
for infringement derived through Geron taking such action shall be applied as
follows: (a) first, to Geron to reimburse Geron for the expenses of the
litigation, including reasonable attorneys' fees, (b) second, to WARF to
reimburse WARF for its reasonable expenses in assisting with such litigation,
including reasonable attorneys' fees, and (c) the balance of any recovery or
damages shall be divided [...***...] ([...***...]) to WARF and [...***...]
([...***...]) to Geron.

        Section 10. Contest of Validity.

        In the event Geron contests the validity of any Licensed Patent, Geron
shall continue to pay royalties with respect to that patent as if such contest
were not underway until the patent is adjudicated invalid or unenforceable by a
court of last resort.

        Section 11. Patent Marking.

        Geron shall insure that it and its sublicensee(s) apply patent markings
that meet all requirements of U.S. law, 35 U.S.C. 287, with respect to all
Products subject to this Agreement.

        Section 12. Product Liability; Conduct of Business.

                A. Geron and its sublicensee(s) shall, at all times during the
term of this Agreement and thereafter, indemnify, defend and hold WARF and the
inventors of the Licensed Patents harmless against all claims and expenses,
including legal expenses and reasonable attorneys fees, arising out of the death
of or injury to any person or persons or out of any damage to property and
against any other claim, proceeding, demand, expense and liability of any kind
whatsoever (other than patent infringement claims) resulting from the
production, manufacture, sale, use, lease, consumption or advertisement of
Products arising from any right or obligation of Geron or any sublicensee
hereunder. Notwithstanding the above, WARF at all times reserves the right to
retain counsel of its own to defend WARF's interests.

                B. Geron warrants that it now maintains and will continue to
maintain liability insurance coverage appropriate to the risk involved in
marketing the products subject to this Agreement and that such insurance
coverage lists WARF and the inventors of the Licensed Patents as additional
insureds. Within ninety (90) days after the execution of this Agreement and
thereafter annually between January 1 and January 31 of each year, Geron will
present evidence to WARF that the coverage is being maintained with WARF and its
inventors listed as additional insureds. In addition, Geron shall provide WARF
with at least 30 days prior written notice of any change in or cancellation of
the insurance coverage.

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<PAGE>   9

        Section 13. Use of Names.

        Geron and its sublicensee(s) shall not use WARF's name, the name of any
inventor of inventions governed by this Agreement, or the name of the University
of Wisconsin in sales promotion, advertising, or any other form of publicity
without the prior written approval of the entity or person whose name is being
used. Except that Geron may use the following statement:

        Geron has entered into a sponsored research agreement with the
        University of Wisconsin -Madison supporting the research of Dr. Thomson
        in the promising area of primate embryonic stem cells. Geron has
        executed a license agreement with WARF regarding the technology.

        Section 14. United States Government Interests.

        It is understood that if the United States Government (through any of
its agencies or otherwise) has funded research, during the course of or under
which any of the inventions of the Licensed Patents were conceived or made, the
United States Government is entitled, as a right, under the provisions of 35
U.S.C. Section 200-212 and applicable regulations of Chapter 37 of the Code of
Federal Regulations, to a nonexclusive, nontransferable, irrevocable, paid-up
license to practice or have practiced the invention of such Licensed Patents for
governmental purposes. Any license granted to Geron in this Agreement shall be
subject to such right. In the event there is assertion by the Government of such
rights, Geron may be entitled to modification of the royalty and license fee
provisions of the Agreement.

        Section 15. Miscellaneous.

        This Agreement shall be construed in accordance with the internal laws
of the State of Wisconsin. If any provisions of this Agreement are or shall come
into conflict with the laws or regulations of any jurisdiction or any
governmental entity having jurisdiction over the parties or this Agreement,
those provisions shall be deemed automatically deleted, if such deletion is
allowed by relevant law, and the remaining terms and conditions of this
Agreement shall remain in full force and effect. If such a deletion is not so
allowed or if such a deletion leaves terms thereby made clearly illogical or
inappropriate in effect, the parties agree to substitute new terms as similar in
effect to the present terms of this Agreement as may be allowed under the
applicable laws and regulations. The parties hereto are independent contractors
and not joint venturers or partners.

        Section 16. Notices.

        Any notice required to be given pursuant to the provisions of this
Agreement shall be in writing and shall be deemed to have been given at the
earlier of the time when actually received as a consequence of any effective
method of delivery, including but not limited to hand delivery, transmission by
telecopier, or delivery by a professional courier service or the time when sent
by certified or registered mail addressed to the party for whom intended at the
address below or at such changed address as the party shall have specified by
written notice, provided that any notice of change of address shall be effective
only upon actual receipt.

        (a)      Wisconsin Alumni Research Foundation
                 Attn: Managing Director
                 614 Walnut Street
                 Madison, Wisconsin  53705

        (b)      Geron Corporation
                 Attn: Vice President of Corporate Development
                 200 Constitution Drive


                                  Page 9 of 17
<PAGE>   10

                 Menlo Park, CA  94025

        Section 17. Integration.

        This Agreement constitutes the full understanding between the parties
with reference to the subject matter hereof, and no statements or agreements by
or between the parties, whether orally or in writing, except as provided for
elsewhere in this Section 17, made prior to or at the signing hereof, shall vary
or modify the written terms of this Agreement. Neither party shall claim any
amendment, modification, or release from any provisions of this Agreement by
mutual agreement, acknowledgement, or otherwise, unless such mutual agreement is
in writing, signed by the other party, and specifically states that it is an
amendment to this Agreement.

        Section 18. Contract Formation and Authority.

        The persons signing on behalf of WARF and Geron hereby warrant and
represent that they have authority to execute this Agreement on behalf of the
party for whom they have signed.

        Section 19. Confidentiality.

        Both parties agree to hold the other party's confidential information in
confidence using procedures at least as stringent as the receiving party uses to
protect its own confidential information. The confidentiality of information
exchanged between the parties shall be governed by the terms of the Confidential
Disclosure Agreement No. 99-0051 between the parties dated February 19, 1999.

        IN WITNESS WHEREOF, the parties hereto have duly executed this Agreement
on the dates indicated below.

   WISCONSIN ALUMNI RESEARCH FOUNDATION

By: /s/ Richard H. Leazer                      Date: 5/6, 1999
   ------------------------------------------
         Richard H. Leazer, Managing Director

   GERON CORPORATION

By: /s/ David L. Greenwood                     Date: 5/6, 1999
   ------------------------------------------

Name and Office:
                -------------------------------------------------

-----------------------------------------------------------------

Reviewed by WARF's General Counsel:

/s/  Elizabeth L.R. Donley
---------------------------
Elizabeth L.R. Donley, Esq.

        April 22, 1999

(WARF's attorney shall not be deemed a signatory to this Agreement.)


                                 Page 10 of 17
<PAGE>   11

        WARF Ref: Thomson-P96014US


                                 Page 11 of 17
<PAGE>   12

                                   APPENDIX A

        A. "Licensed Patents" shall refer to and mean those patents and patent
applications listed on Appendix B attached hereto that are in countries in the
Licensed Territory and any subsequent patent application owned by WARF,
including divisionals, continuations, continuations-in-part, reissues, and
reexaminations in a country in the Licensed Territory.

        B. "Products" shall refer to and mean Therapeutic Products and
Diagnostic Products.

        C. "Therapeutic Products" shall refer to and mean products or services
other than Diagnostic Products that (i) are used in the treatment of disease in
humans, and (ii) employ, are in any way produced by the practice of, are
identified using or arise out of any research involving the inventions claimed
in the Licensed Patents or that would otherwise constitute infringement of any
claims of the Licensed Patents.

        D. "Diagnostic Products" shall refer to and mean products or services
that (i) are used in the diagnosis, prognosis, screening or detection of disease
in humans, and (ii) employ, are in any way produced by the practice of, are
identified using or arise out of any research involving the inventions claimed
in the Licensed Patents or that would otherwise constitute infringement of any
claims of the Licensed Patents.

        E. "Research Products" shall refer to and mean products or services that
(i) are used in research as research tools which would infringe the claims of
patented technology owned by Geron or which Geron has a right or license to use
other than the Licensed Patents, and (ii) which employ, are in any way produced
by the practice of, are identified using or arise out of any research involving
the inventions claimed in the Licensed Patents or that would otherwise
constitute infringement of any claims of the Licensed Patents. Research Products
specifically excludes the Materials.

        F. "Selling Price" shall mean, in the case of Products that are sold,
the price to the end user of Products (regardless of uncollectible accounts)
less any shipping costs, allowances because of returned Products, value added
taxes (or comparable duties as required in each country) or sales taxes. For
purposes of this Agreement, the term "price to the end user" shall mean the
price paid to Geron for Product by its customer assuming an arm's length
transaction. In the event that Geron sells Product to an affiliate, the price
shall be deemed that amount that Geron would have received if it had sold
Product to an unaffiliated third-party. The "Selling Price" for a Product that
is transferred to a third party for promotional purposes without charge or at a
discount which exceeds [...***...] percent ([...***...]%) of the annual total
of Products sold shall be the average invoice price to the end user of that type
of Product during the applicable calendar quarter. All taxes, assessments, or
other charges of any kind which may be imposed on sales of Products by any
government outside of the United States or any political subdivision of such
government with respect to any amounts payable to WARF pursuant to this
Agreement shall be paid by Geron.

        G. "Development Report" shall mean a written account of Geron's progress
under the development plan having at least the information specified on Appendix
D to this Agreement, and shall be sent to the address specified on Appendix D.

        H. "Materials" shall refer to and mean the primate, including human,
embryonic stem cells claimed in the Licensed Patents.

--------

[...***...] = MATERIAL HAS BEEN OMITTED PURSUANT TO A REQUEST FOR CONFIDENTIAL
TREATMENT AND HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
COMMISSION.


                                 Page 12 of 17
<PAGE>   13

        I. "Licensed Field" shall be limited to (i) Research Products, (ii)
Therapeutic Products and (iii) Diagnostic Products developed from and/or
incorporating the Materials as precursors to the following cell types as well as
the following cell* types: [...***...]

        J. "Licensed Territory" shall be worldwide.

--------

[...***...] = MATERIAL HAS BEEN OMITTED PURSUANT TO A REQUEST FOR CONFIDENTIAL
TREATMENT AND HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
COMMISSION.


                                 Page 13 of 17
<PAGE>   14

                                   APPENDIX B

                                LICENSED PATENTS

<TABLE>
--------------------------------------------------------------------------------------------------------------------
<S>                          <C>                  <C>                    <C>               <C>
          REFERENCE                                        PATENT              ISSUE              APPLICATION
           NUMBER                    COUNTRY               NUMBER               DATE             SERIAL NUMBER
--------------------------------------------------------------------------------------------------------------------
</TABLE>

PRIMATE EMBRYONIC STEM CELLS (THOMSON)

<TABLE>
--------------------------------------------------------------------------------------------------------------------
<S>                          <C>                  <C>                    <C>               <C>
   [...***...]                 UNITED STATES                                                  [...***...]
--------------------------------------------------------------------------------------------------------------------
</TABLE>


PRIMATE EMBRYONIC STEM CELLS (THOMSON)

<TABLE>
--------------------------------------------------------------------------------------------------------------------
<S>                          <C>                  <C>                    <C>               <C>
   P96014US                    UNITED STATES            5,843,780          12/01/98
--------------------------------------------------------------------------------------------------------------------

   [...***...]                 PCT                                                            [...***...]
--------------------------------------------------------------------------------------------------------------------

   [...***...]                 CANADA                                                         [...***...]
--------------------------------------------------------------------------------------------------------------------

   [...***...]                 EPO                                                            [...***...]
--------------------------------------------------------------------------------------------------------------------
</TABLE>


PRIMATE EMBRYONIC STEM CELLS WITH [...***...] GENES (THOMSON)

<TABLE>
--------------------------------------------------------------------------------------------------------------------
<S>                          <C>                  <C>                    <C>               <C>
   [...***...]                 UNITED STATES                                                  [...***...]
--------------------------------------------------------------------------------------------------------------------
</TABLE>

--------

[...***...] = MATERIAL HAS BEEN OMITTED PURSUANT TO A REQUEST FOR CONFIDENTIAL
TREATMENT AND HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE
COMMISSION.


                                 Page 14 of 17
<PAGE>   15

                                   APPENDIX C

                               WARF ROYALTY REPORT

   AGREEMENT NO: ______________ INVENTOR: ______________ P#: P _________________

 PERIOD COVERED: From:     /   / 199           Through:     /   / 199
                      ________________________         _________________________
    PREPARED BY: ______________________________   DATE: ________________________
    APPROVED BY: ______________________________   DATE: ________________________

        If license covers several major product lines, please prepare a
        separate report for each line. Then combine all product lines
        into a summary report.

    REPORT TYPE: [ ] SINGLE PRODUCT LINE REPORT: _______________________________

                 [ ] MULTIPRODUCT SUMMARY REPORT. Page 1 of ______ Pages

                 [ ] PRODUCT LINE DETAIL.  Line: _________ Tradename: __________
                                           Page: _________

REPORT CURRENCY: [ ] U.S. DOLLARS    [ ] OTHER ________________________________

<TABLE>
------------------- ----------------- ---------------- ----------------- ---------------- ----------------------------------
                         GROSS            * LESS:            NET             ROYALTY            PERIOD ROYALTY AMOUNT
     COUNTRY             SALES          ALLOWANCES          SALES             RATE           THIS YEAR         LAST YEAR
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
<S>                 <C>               <C>              <C>               <C>              <C>               <C>
U.S.A.
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
Canada
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
Europe:
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
Japan
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
Other:
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------

------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
TOTAL:
------------------- ----------------- ---------------- ----------------- ---------------- ----------------- ----------------
</TABLE>

Total Royalty: _______ Conversion Rate: ______ Royalty in U.S. Dollars: $_______

        The following royalty forecast is non-binding and for WARF's
        internal planning purposes only:

Royalty Forecast Under This Agreement: Next Quarter:____ Q2:____ Q3:____ Q4:____

        *On a separate page, please indicate the reasons for returns or
         other adjustments if significant.

         Also note any unusual occurrences that affected royalty amounts
         during this period.

         To assist WARF's forecasting, please comment on any significant
         expected trends in sales volume.

                                 Page 15 of 17
<PAGE>   16

                                   APPENDIX D

                               DEVELOPMENT REPORT

A. Date development plan initiated and time period covered by this report.

B. Development Report (4-8 paragraphs).

     1.   Activities completed since last report including the object and
          parameters of the development, when initiated, when completed and the
          results.

     2.   Activities currently under investigation, i.e., ongoing activities
          including object and parameters of such activities, when initiated,
          and projected date of completion.

C. Future Development Activities (4-8 paragraphs).

     1.   Activities to be undertaken before next report including, but not
          limited to, the type and object of any studies conducted and their
          projected starting and completion dates.

     2. Estimated total development time remaining before a product will be
commercialized.

D. Changes to initial development plan (2-4 paragraphs).

     1.   Reasons for change.

     2. Variables that may cause additional changes.

E. Items to be provided if applicable:

     1.   Information relating to Product that has become publicly available,
          e.g., published articles, competing products, patents, etc.

     2.   Development work being performed by third parties other than Geron to
          include name of third party, reasons for use of third party, planned
          future uses of third parties including reasons why and type of work.

     3.   Update of competitive information trends in industry, government
          compliance (if applicable) and market plan.

PLEASE SEND DEVELOPMENT REPORTS TO:

     Wisconsin Alumni Research Foundation
     Attn.: Contract Coordinator
     614 Walnut Street
     P.O. Box 7365
     Madison, WI  53707-7365


                                 Page 16 of 17
<PAGE>   17

                                   APPENDIX E

                                DEVELOPMENT PLAN

        A development plan of the scope outlined below shall be submitted to
WARF by Geron within thirty (30) days of the execution of this Agreement. In
general, the plan should provide WARF with a summary overview of the activities
that Geron believes are necessary to bring Products to the marketplace.

                               Estimated
                               Start Date                           Finish Date
                               ----------                           -----------

I. Development Program

     A.   Development Activities to be Undertaken

          (Please break activities into subunits with the date of completion of
           major milestones)

          1.

          2.

     B.   Estimated Total Development Time

II. Governmental Approval

     A.   Types of submissions required

     B.   Government agency e.g. FDA, EPA, etc.

III. Proposed Market Approach

IV. Competitive Information

     A.   Potential Competitors

     B.   Potential Competitive Devices/Compositions

     C.   Known Competitor's plans, developments, technical achievements

     D.   Anticipated Date of Product Launch

Total Length: approximately 2-3 pages



                                 Page 17 of 17