Third party reproduction refers to a process where another person provides sperm or eggs or where another woman provides her uterus so that a woman can have a child. Thus the reproductive process goes beyond the traditional father-mother model. However, the third party's involvement is limited to the reproductive process and does not extend into the raising of the child. One can separate:
- Sperm donation. A third party provides sperm that can be used for insemination of the future mother or to fertilise an ovum for re-insertion of the resulting embryo into the mother, or by embryo transfer into a surrogate mother.
- Ovum donation. An egg donor provides ova for fertilization in the IVF process. The embryo is placed into the uterus/womb of the future mother (embryo transfer).
- Embryo donation, with unused embryos after the woman for whom they were originally created has successfully carried one or more pregnancies to term, or where embryos are specifically created for donation using donor eggs and donor sperm.
- Gestational carrier. A woman carries a baby through the pregnancy for another person. This involves the use of IVF as the embryo is implanted by embryo transfer.
Thus a child can have a genetic and social (non-genetic, non-biologic) father, and a genetic, gestational, and social (non-biologic) mother, and any combinations thereof. Theoretically a child thus could have 5 parents.
Surrogacy includes, in its wider sense, all situations where a surrogate carries a pregnancy for another person. Recently, there has been a tendency to separate the gestational carrier situation from the "true" surrogate restricting the term for a woman who provides a combination of ovum donation and gestational carrier services.
In a 'conventional surrogacy', a surrogate agrees to be inseminated with the sperm of the male partner of the 'commissioning' couple, or with the sperm of one of the male partners in a same-sex relationship, or with sperm provided by a sperm donor. The surrogate is inseminated, conceives, and hands over the baby at the completion of the pregnancy. In conventional surrogacy, the egg which is fertilized is therefore that of the surrogate. A famous case involving paternity rights and surrogacy is the Baby M case.
In a 'gestational surrogacy', a surrogate agrees to the implantation in her of an embryo which may be created either by using an egg provided by another woman who may be part of a 'commissioning' couple, or she may be a single woman. Alternatively, an egg provided by a donor may be used to create the embryo. The embryo implanted in the surrogate may be fertilised using sperm from the male partner of the 'commissioning couple', or by using sperm provided by a sperm donor.
Embryo donation is where extra embryos from a successful IVF of a couple are given to other couples or women for transfer with the goal of producing a successful pregnancy. Embryos for embryo donation may also be created specifically for embryo transfer using donor eggs and sperm, or in some cases donor eggs and donor sperm. It may thus be seen as a combination of sperm donation and egg donation, since what is donated is a combination of these. Such embryos may also be donated to a 'commissioning' woman or a 'commissioning' couple and gestated by a surrogate where, for example, the 'commissioning' woman or the woman of the 'commissioning' couple is infertile and is unable to bring a pregnancy to full term on medical grounds, or is unwilling for social, medical or other reasons, to do so.
- Annotated Bibliography for Children and Parents of Third Party Reproduction Compiled by the Education Committee, Spring 2007
- UK Donorlink (UK Voluntary Information Exchange and Contact Register for donors and donor-conceived people)
-  THIRD PARTY REPRODUCTION(Sperm, egg, and embryo donation and surrogacy) A Guide for Patients
-  Different treatments and methods available for Third Party Reproduction
-  Various articles on Third Party Reproduction
-  Third-Party Reproduction, A Comprehensive Guide. Editor. Goldfarb, James M