Like so many momentous events in the lives of young women, this one began with a missed period. Julia* had been on oral contraceptives for years, but when she went off the pill, her period did not start up again. Her doctor told her this was not unusual, but months later she still was not menstruating and had begun to experience hot flashes. Hormone levels showed she had a condition called primary ovarian insufficiency—in other words, premature menopause. She was 22 years old.