|You and your husband have been trying to have a baby for years. After three miscarriages, your doctor refers you to an infertility specialist, who recommends in vitro fertilization ("in vitro" is Latin for "in dish," as opposed to "in vivo," or "in body"). IVF involves fertilizing your eggs with your husband's sperm in a petri dish and then transferring some of the resulting embryos—genetically related to both of you—into your womb.
You decide to do IVF, and you and your husband, with the help of the lab, successfully create eight embryos. After a few days, the embryos are ready to be transferred to your uterus where, hopefully, at least one will implant and grow to a healthy baby. The time comes for your doctor to choose the embryos for transfer. Because of the risk of multiple births, the doctor will select and transfer no more than three from the eight you have created.