Cord blood bank
A cord blood bank is a facility which stores umbilical cord blood for future use.  Both private and public cord blood banks have developed since the mid to late 1990s in response to the success of cord blood transplants in treating diseases of the blood and immune systems, such as Fanconi's anemia and leukemia.  Cord blood, once seen as waste to be discarded after a birth, is now viewed as a precious resource.
Cord blood contains hematopoietic stem cells, progenitor cells which can form red blood cells, white blood cells and platelets. Cord blood stem cells are not embryonic stem cells, a pluripotent stem cell, which theoretically can develop into any type of human cell.  Cord blood cells are currently used to treat blood and immune system related genetic diseases, cancers and blood disorders.  There is ongoing research to identify additional applications for cord blood.
Public banks accept donations to be used for anyone in need. However, there are very strict regulations which public banks need to follow in order to enable the donated units to be added to a registry.  Generally an expectant mother interested in donation should contact the bank before the 34th week of pregnancy.  The National Marrow Donor Program has a list of public cord blood banks on their website. Once the blood is donated, it loses all identifying information after a short period of initial testing, so that families will not be able to retrieve their blood later.
Private banking allows families to preserve their blood for their own use. For-profit private banks charge a fee of around $2000  to preserve a newborn's cord blood for possible use by the family later.
Public cord blood banking is strongly supported by the medical community, but private cord blood banking is generally not recommended unless there is a family history of specific genetic diseases.  Public and private banks offer free programs to store the cord blood of babies whose family members have a condition which can be treated with the blood cells.

# The collection process
When a mother chooses to donate cord blood (which is rich in blood stem cells) or store it for private use, the initial collection process is the same and poses no danger to mother or baby if done properly (see below for discussion of medical issues).
There are two methods to collection, in-utero and ex-utero.  During in-utero collection, the cord blood is collected while the doctor or midwife is waiting for the placenta to deliver naturally. There is a period of 5-10 minutes after the baby is delivered and before the placenta is delivered where there is ample time to collect the cord blood.  During an ex-utero collection, the placenta is delivered and then placed in a sterile supporting structure with the umbilical cord hanging through the support.
Additional stem cells may be collected from the placenta via Placenta Cord Banking. After the health care provider draws the cord blood from the umbilical cord, the placenta is couriered to the stem cell laboratory where it is processed for additional stem cells.
An adequate cord blood collection requires at least 75 mL in order to ensure that there will be enough cells to be used for a transplantation.  After the collection, the cord blood unit is shipped to the lab and processed and then cryopreserved.  There are many ways to process a cord blood unit and there are differing opinions on what is the best way.  Some processing methods separate out the red blood cells and remove them while others keep the red blood cells.  However, the unit is processed, a cryopreservant is added to the cord blood to allow the cells to survive the cyrogenic process.  After the unit is slowly cooled to -90 Celsius it can then be added to a liquid nitrogen tank which will keep the cord blood unit frozen at -196 Celsius.  The slow freezing process is important to keep the cells alive during the freezing process. Before the blood is stored for later use, it undergoes viral testing, including tests for HIV and Hepatitis B and C and tissue typing (to determine HLA type).

# Benefits
Cord blood stem cells are currently used to treat blood and immune system related genetic diseases, cancers, and blood disorders.  Because of medical issues around using one's own cells, as well as the availability of cells, in nearly every instance the treatments are done using cells from another donor, with the vast majority being unrelated donors.

# Issues common to all cord blood banks
Cord blood banking is still in its developmental stages and there are issues in both private and public banking which need to be resolved before it will become a widely established practice.  The main concern of cord blood banking, private or public, is that the long-term viability of cryogenically frozen cord blood has yet to be firmly established.
Other established treatments may be more suitable for the patient, rather than cord blood transplants.
It may become possible to obtain the needed blood or more generalized stem cells by other means, such as from the bloodstream of an adult or from tissue culture.

# Public bank issues
A primary concern with public banking is how to ensure the safety of the cord blood. Because of privacy concerns, it is agreed by most ethical review boards that blood donated to a public bank cannot be permanently linked to the donor. Although cord blood which is donated goes through a series of tests for potentially harmful genetic disorders and viruses, some genetic disorders such as congenital anemias or immunodeficiencies might not become apparent in the donor for months or years, by which time all identifying information has long been removed. Because the recipient of the blood could also develop these disorders, this is an important concern.
The larger obstacle facing public banks is that the costs required to maintain them has prevented more than a handful from opening.   Because public banks do not charge storage fees, many medical centers do not have the funds required to establish and maintain them.
Because of donation patterns, differing racial groups have different likelihood of finding a match through a public cord blood bank.  Caucasians find a match 88% of the time, while other races match just 58% of the time.  Public bank advocacy groups are particularly trying to encourage donations by members of non-Caucasian racial groups.

# Private bank issues
Private cord blood banking also poses problems. The cost of some private banks also prevents them from being an option available to all families.  Private cord blood banks are sometimes criticized for preying upon the insecurity of new parents, on the grounds that currently the chances of a child needing his or her own cord blood are very small, whereas storage fees at some private banks are high.  The ability to use the cord blood may also depend on the long-term commercial viability of the enterprise. Accordingly, whether cord blood banking is a worthwhile expenditure for the expectant parent depends in part upon whether the expenditure is offset by the likelihood of ultimately using the cord blood and the benefits of such use.
It is important to ensure the credentials of any potential private bank. For example, in the UK private banks are accredited by the Medicines and Healthcare Products Regulatory Agency and Human Tissue Authority.

## Low likelihood of use
Cord blood is "very unlikely ever to be used" by the donor. Estimates of the odds of using banked cord blood range from 1:2,700 to 1:20,000.  "According to research in the Journal of Pediatric Hematology/Oncology (1997, 19:3, 183-187), the odds that a child will need to use his or her own stem cells by age twenty-one for current treatments are about 1:2,700, and the odds that a family member would need to use those cells are about 1:1,400." The likelihood of use for those lacking a family history of specific genetic diseases is much lower than the average across the entire population. A 2005 article states, "The probability of needing an autologous transplant is less than one in 20,000, although commercial providers quote figures at least an order of magnitude higher, often confusing prearranged usage in at risk children with unanticipated use in those at low risk."  One of the reasons for low likelihood of use is that effective alternative treatments are available.
A familial relationship does not ensure a match allowing transplant, as genetics vary.  Even between siblings, there is a 25% chance that the cord blood will not be suitable, and a 50% chance it will be a partial match.

## Legality and ethics
For those at low risk, private storage of one's own cord blood is unlawful in Italy and France, and discouraged in some other European states.
In 2004, the European Group on Ethics in Science and New Technologies advised the European Commission that "The legitimacy of commercial cord blood banks for autologous  use should be questioned as they sell a service, which has presently, no real use regarding therapeutic options. Thus they promise more than they can deliver. The activities of such banks raise serious ethical criticisms."
Doctors and patients have stated that the claims of some private cord blood banks are deceptive and misleading.

## Medical societies do not recommend private banking
The Royal College of Obstetricians and Gynaecologists 2006 opinion states, "There is still insufficient evidence to recommend directed commercial cord blood collection and stem-cell storage in low-risk families."
The policy of the American Academy of Pediatrics policy states that "private storage of cord blood as 'biological insurance' is unwise" unless there is a family member with a current or potential need to undergo a stem cell transplantation. 
Similarly, the American College of Obstetricians and Gynecologists does not recommend private cord blood banking.

## Safety and effectiveness of using one's own cells unclear
Using one's own cord blood cells might not be wise or effective, especially in cases of childhood cancers and leukemia. Children who develop an immunological disorder often are unable to use their own cord blood for transplant because the blood also contains the same genetic defect.  Nearly all of the transplants using privately banked cord blood have gone to relatives with pre-existing conditions, not to the donors.

## Usability of one's own sample unknown
Most cord blood samples - up to 75% - may be too small to be used for transplantation, because they don't contain enough stem cells.  While a private bank will store a sample, the sample may be too small to be usable even by a child.  Larger numbers of blood cells are required for adults, due to their larger body mass.

## Ownership of cord blood unclear
As of 2007, contracts of the largest cord blood banks do not explicitly state that the cord blood belongs to the donors and child with all the rights and privileges one would reasonably expect from ownership.  The ambiguity leaves open future uses not approved by the donors and child.  Examples of possible uses without the donor's consent include cloning, research, or partial sale.  Some contracts fail to spell out the rights of the donors requesting termination of storage: e.g. the right to request and verify destruction of the samples.

# Medical issues
Concerns have been raised that the current interest in cord blood could cause a perception that cord blood is 'unused' by the birth process, thus decreasing the amount of blood which is infused into the child as part of the birth process.  The pulsation of the cord pushes blood into the child, and it has been recommended that the cord cease pulsation prior to clamping.  With the demand for cord blood increasing, there is a possibility that the cord could be clamped prematurely to preserve even more 'extra' cord blood.  This action could have detrimental effects on the child's future development.
It is important to note however, that it is considered standard practice by cord blood banks to request that the delivering physician not alter the regular course of the birthing process, and that, if delivering in a hospital under standard procedures, collection of cord blood will not have any effect on the normal birthing process.
The American Academy of Pediatricians notes: "if cord clamping is done too soon after birth, the infant may be deprived of a placental blood transfusion, resulting in lower blood volume and increased risk for anemia."
The Journal of the American Academy of Pediatrics published an article in April 2006 recommending that clamping be delayed to reduce anemia and improve neonatal iron storage.

# Confusion with embryonic stem cells
Much of the general public in the United States is somewhat aware of embryonic stem cells because of the controversy associated with them.  However, cord blood stem cells (hematopoietic stem cells) are not embryonic stem cells (pluripotent stem cells).