A microscopic image of a needle (left) injecting sperm cells directly into a human egg (center). The broad object at right is a pipette used to hold the ovum steady. (Phototake NYC. Reproduced by permission.)

Forin vitrofertilization, hormones are administered to the patient, and then eggs are harvested from her ovaries (A). The eggs are fertilized by sperm donated by the father (B). Once the cells begin to divide, one or more embryos are placed into the woman's uterus to develop (C). (Illustration by GGS Inc.)