full surrogacy) was first achieved in April 1986. It takes place when an embryo created by in vitro fertilization (IVF) technology is implanted in a surrogate, sometimes called a gestational carrier. Gestational surrogacy has several forms, and in each form, the resulting child is genetically unrelated to the surrogate: The embryo is created using the intended father's sperm and the intended mother's eggs; The embryo is created using the intended father's sperm and a donor egg; The embryo is created using the intended mother's egg and donor sperm; A donor embryo is transferred to a surrogate. Such an embryo may be available when others undergoing IVF have embryos left over, which they donate to others. The resulting child is genetically unrelated to the intended parent(s). Risks The embryo implanted in gestational surrogacy faces the same risks as anyone using IVF would. Preimplantation risks of the embryo include unintentional epigenetic effects, influence of media which the embryo is cultured on, and undesirable consequences of invasive manipulation of the embryo. Often, multiple embryos are transferred to increase the chance of implantation, and if multiple gestations occur, both the surrogate and the embryos face higher risks of complications. Gestational surrogates have a smaller chance of having hypertensive disorder during pregnancy compared to mothers pregnant by oocyte donation. This is possibly because gestational carriers tend to be healthier and more fertile than women who use oocyte donation. Gestational carriers also have low rates of placenta previa / placental abruptions (1.1-7.9%). Children born through singleton IVF surrogacy have been shown to have no physical or mental abnormalities compared to those children born through natural conception. However, children born through multiple gestation in gestational carriers often result in preterm labor and delivery, resulting in prematurity and physical and/or mental anomalies. Outcomes Among gestational surrogacy arrangements, between 19–33% of gestational surrogates will successfully become pregnant from an embryo transfer. Of these cases, 30–70% will successfully allow the intended parent(s) to become parent(s) of the resulting child. For surrogate pregnancies where only one child is born, the preterm birth rate in surrogacy is marginally lower than babies born from standard IVF (11.5% vs 14%). Babies born from surrogacy also have similar average gestational age as infants born through in vitro fertilization and oocyte donation; approximately weeks. Preterm birth rate was higher for surrogate twin pregnancies compared to single births. There are fewer babies with low birth weight when