For the last decade, women have been bombarded with warnings that fertility falls off a cliff after age 35. Now, though, it turns out the panic might have been overblown. In The Atlantic, Jean Twenge writes that when she scoured the medical literature, she found that “statistics on women’s age and fertility—used by many to make decisions about relationships, careers, and when to have children—were one of the more spectacular examples of the mainstream media’s failure to correctly report on and interpret scientific research.” Take, for example, the oft-cited statistic that one in three women between 35 and 39 will fail to get pregnant after a year of trying. It turns out that it’s based on French birth records from 1670 to 1830. “In other words,” she writes, “millions of women are being told when to get pregnant based on statistics from a time before electricity, antibiotics or fertility treatment.” There are surprisingly few well-designed studies of 20th-century women’s fertility, but those that exist offer reasons for optimism. “Fertility does decrease with age, but the decline is not steep enough to keep the vast majority of women in their late 30s from having a child,” writes Twenge.
Even though some long-held stats are based on records from the 18th century.