The standard embryo transfer procedure involves impregnating a volunteer (or paid) woman by artificial insemination with sperm from an infertile wife's husband. Five day's after conception, the embryo is flushed out (“lavaged”) and transferred to the infertile woman's uterus. The embryo may also be the result of in vitro fertilization (IVF).

In artificial insemination, the precursor to IVF, only the male gamete is isolated from the body. In the IVF procedure, both male and female gametes are isolated.

Embryo transfer takes this process one step farther: an embryo that is conceived (usually by artificial insemination) is removed and transferred to another woman.

“Surrogate motherhood” usually involves the artificial insemination of a woman with a husband's sperm if his wife is infertile or does not want to carry a pregnancy to term for a variety of reasons. In some cases, the surrogate is implanted with the couple's embryo after IVF. The surrogate receives anywhere from $10,000 to $30,000 for carrying the child, and she relinquishes him to the contracting couple immediately after birth. This practice is sometimes called “Rent-a-Womb” or “mercenary motherhood.”

Interestingly most contracts between the surrogate and the husband and wife insist the surrogate abort the child if genetic tests show abnormalities unacceptable to the husband and wife—in direct conflict with the surrogate woman's alleged “right to choose.” Proponents of “surrogate motherhood” deny any infringement of rights, of course, because they say that the baby in question is mere property under contract.

In response to a question about whether “surrogate motherhood” is morally licit, the Congregation for the Doctrine of the Faith in its 1987 document Donum Vitae (Instruction on Respect for Human Life in its Origin and the Dignity of Procreation: Replies to Certain Questions of the Day) responded:

“No, for the same reasons which lead one to reject artificial fertilization: For it is contrary to the unity of marriage and to the dignity of the procreation of the human person. Surrogate motherhood represents an objective failure to meet the obligations of maternal love, of conjugal fidelity, and of responsible motherhood; it offends the dignity and the right of the child to be conceived, carried in the womb, brought into the world, and brought up by his own parents; it sets up, to the detriment of families, a division between the physical, psychological, and moral elements which constitute those families.”

Source: The Facts of Life: An Authoritative Guide to Life and Family Issues, by Brian Clowes PhD (Human Life International, Front Royal, Va.). Reprinted with permission.