EXHIBIT 10.3

                                 PROMISSORY NOTE
$14,000                                                         Date May 7, 2002

For value received,  the undersigned Erik Van Horn (the "Promisor")  promises to
pay to the order of Vitro  Diagnostics,  Inc.  ("Payee") at 12635 East  Montview
Blvd,  Suite  218,  Aurora,  CO 80010 (or at such  other  place as the Payee may
designate in writing) the sum of  $14,000.00  (Fourteen  thousand  dollars) plus
interest from April 22, 2002, on the unpaid principle at a rate of 5% per annum.

It is  understood  between  the  parties  that the entire  amount  loaned to the
promisor is to be  immediately  applied to the  purchase  of Vitro  Diagnostic's
common stock underlying  options granted to the Promisor on May 8, 1992. Exhibit
A contains a copy of this stock option agreement.

Unpaid  principal after the due date shown below shall accrue interest at a rate
of 7.5% annually until paid in full.

Promisor  shall make minimum  monthly  payments of not less than $1000 per month
beginning  May 31,  2002.  This amount is to be paid in the form of deduction in
salary,  in lieu of salary,  or consulting  arrangement by agreement between the
Promisor  and the Payee.  All  payments  on the Note  shall be applied  first in
payment of accrued  interest and any remainder in payment of  principal.  Unpaid
principal  and  accrued  interest  shall be  payable in full on or before May 8,
2004, the "Due Date". The Promisor agrees to provide  collateral for the note by
pledging to the Payee 116,700  shares of common stock  acquired upon exercise of
the option. Payee shall hold the certificates representing the collateral common
stock pending  payment in full of the note.  The Promisor  reserves the right to
prepay this Note, in whole or in part,  prior to the Due Date with no prepayment
penalty.

If any payment  obligation  under this Note is not paid when due,  the  Promisor
agrees to pay all  costs of  collection,  including  reasonable  attorney  fees,
whether or not a lawsuit is commenced as part of the collection process.

If any of the  following  events  of  default  occur,  the  Note  and any  other
obligations of the Promisor to the payee shall become due with 30 days notice.

1) the  failure  of the  Promisor  to pay any  amount of the  principal  and any
accrued  interest  when due; 2) the death of the  Promisor(s);  3) the filing of
bankruptcy  proceedings  involving the Promisor as a Debtor;  4) the application
for  appointment  of a  receiver  for the  Promisor;  5) the making of a general
assignment for the benefit of the Promisor's creditors; 6) the insolvency of the
Promisor.

<PAGE>

In  addition,  the  Promisor  shall be in default if there is a sale,  transfer,
assignment,  or any other  disposition of any assets pledged as security for the
payment of this Note, or if there is a default in any security  agreement  which
secures this Note.

If any  one or  more  of the  provisions  of  this  Note  are  determined  to be
unenforceable,  in whole or in part,  for any reason,  the remaining  provisions
shall remain fully operative.

All payments of  principal  and interest on this Note shall be paid in the legal
currency of the United States. Promisor waives presentment for payment, protest,
and notice of protest and nonpayment of this Note.

No renewal or extension of this Note,  delay in enforcing any right of the Payee
under this note,  or assignment by Payee of this Note shall affect the liability
of the Promisor.  All rights of the Payee under this Note are cumulative and may
be exercised concurrently or consecutively at the Payee's option.

This  Note  shall be  construed  in  accordance  with  the laws of the  State of
Colorado.

Executed on this 8th day of May, 2002

By: /s/ Erik Van Horn
    ------------------
        Erik Van Horn