Fecundity in women peaks in their 20s and declines in their 30s; by their early 40s, up to 50% of women have been affected by infertility, whether it is their own or their husband's. After menopause, almost all women are infertile. Menopause strikes most women in their late 40s, although it may strike before they become 40 or after they reach the age of 60.