in vitro fertilization, technique for conception of a human embryo outside the mother's body. Several ova, or eggs, are removed from the mother's body and placed in special laboratory culture dishes (Petri dishes); sperm from the father are then added, or in many cases a sperm is injected directly into an ovum, a process known as intracytoplasmic sperm injection. If fertilization is successful, a fertilized ovum (or several fertilized ova), after undergoing several cell divisions, is either transferred to the mother's or a surrogate mother's body for normal development in the uterus, or frozen for later implantation. Eggs also can be frozen and fertilized later. In vitro maturation is when the ova are extracted and then matured in a laboratory (instead of in the mother's body) before they are fertilized.

First developed by Patrick C. Steptoe and Robert G. Edwards of Great Britain (where the first "test-tube baby" was born under their care in 1978), the technique was devised for use in cases of infertility when the woman's fallopian tubes are damaged or the man's sperm count is low. It is also used to enable prospective parents with other reproductive problems (e.g., inability to produce eggs, poor sperm quality, or endometriosis) to bear a child, and can be used in conjunction with embryo biopsy, or preimplantation genetic diagnosis, to enable parents to have a child who is free of some inheritable defects or diseases. In embryo donation (also called embryo adoption), frozen embryos that are not needed by the mother are donated for implantation to a woman or couple who are infertile but wish to have, and are capable of bearing, children. The use of in vitro fertilization has resulted in the birth of more than a million babies. Nevertheless, the technique has raised legal, ethical, and religious issues, including concerns regarding legal custody of frozen embryos following divorce and questions regarding the appropriateness of the procedure posed by the Roman Catholic Church and other institutions.

See also artificial insemination; fertilization; reproductive system; surrogate mother.

or test-tube conception

Procedure, used to overcome infertility, in which eggs are removed from a woman, fertilized with sperm outside the body, and inserted into the uterus of the same or another woman. The first child thus conceived was born in 1978. IVF includes extraction of eggs, collection of sperm, fertilization in culture, and introduction into the uterus at the eight-cell stage. In a successful procedure, the embryo is implanted in the uterine wall, and pregnancy begins. The most common problem is failed implantation. IVF has been a source of moral, ethical, and religious controversy since its development.

Learn more about in vitro fertilization (IVF) with a free trial on Britannica.com.