Surrogate mothers carry and give birth to a child for another, to whom it is then transferred. The transaction may involve payment, or may be done without charge by a relative. Use of a surrogate mother is usually the response of a childless couple who are unable to naturally conceive or go through a pregnancy. The surrogate mother may receive an artificially fertilized egg from the parents' gametes, or from anonymous sources, as an womb implant, or she may become pregnant naturally by having sexual intercourse with the father.
In 1997, an Italian woman carried two embryos at once for two different couples, in return for which she received expenses. The implantation and births had to be performed outside of Italy, where medical codes forbid surrogate motherhood.