- a specialized technique by which an ovum, especially a human one, is fertilized by sperm outside the body, with the resulting embryo later implanted in the uterus for gestation.
- a technique enabling some women who are unable to conceive to bear children. Egg cells removed from a woman's ovary are fertilized by sperm in vitro; some of the resulting fertilized egg cells are incubated until the blastocyst stage, which are then implanted into her uterus
