Pregnancy over age 50 has, over recent years, become more possible for women, due to recent advances in assisted reproductive technology, in particular egg donation. Typically, a woman's fecundity ends with menopause, which by definition is 12 consecutive months without having had any menstrual flow at all. During perimenopause, the menstrual cycle and the periods become irregular and eventually stop altogether, but even when periods are still regular, the egg quality of women in their forties is typically dramatically lower than in younger women, making the likelihood of conceiving a healthy baby also dramatically lower, particularly after age 42. Men, in contrast, generally remain fertile throughout their lives, although the risk of genetic defects is greatly increased due to the paterna