Today, in vitro fertilization (IVF) is practically a household word. But not so long ago, it was a mysterious procedure for infertility that produced what were then known as "test-tube babies." Louise Brown, born in England in 1978, was the first such baby to be conceived outside her mother's womb.
Unlike the simpler process of artificial insemination -- in which sperm is placed in the uterus and conception happens otherwise normally -- IVF involves combining eggs and sperm outside the body in a laboratory. Once an embryo or embryos form, they are then placed in the uterus. IVF is a complex and expensive procedure; only about 5% of couples with infertility seek it out. However, since its introduction in the U.S. in 1981, IVF and other similar techniques have resulted in more than 200,000 babies.