A surrogate mother is a lady who carries a baby for another person or people, usually an infertile couple. There are two different types of surrogacy:

Traditional Surrogacy:
Here, the surrogate mother is artificially inseminated with the sperm of the intended father or sperm donor. The surrogate's own egg will be used, thus she will be the genetic mother of the resultant child.

Gestational Surrogacy:
In a gestational surrogacy, the surrogate mother is not genetically related to the child. Eggs are extracted from the intended mother or egg donor and mixed with sperm from the intended father or sperm donor in vitro. The embryos are then transferred into the surrogate's uterus. Embryos that are not transferred can be frozen and used for transfer at a later time if the first transfer does not result in pregnancy.