Surrogate motherhood, which literally means “substitute motherhood,” is a problematic phrase, for it draws together two phenomena—biological reproduction and mothering—that the practice of surrogacy in fact radically separates. A surrogate mother is a woman who agrees to become pregnant and bear a child for another couple, usually because the female partner is infertile or unable to sustain a pregnancy. In traditional surrogacy, the surrogate is artificially inseminated with sperm from the intended father (or a donor), in which case the resulting child is her genetic offspring.

The trend in recent years, however, has been toward gestational surrogacy through in vitro fertilization; in these cases, an embryo produced with another woman's ovum is implanted in the surrogate. Typically, surrogate arrangements are formalized through legal contracts and entail ...