If you are a woman over 35 without children (or even one who has kids but would still like more), you’ve probably endured comments about how the clock is ticking and you better get to it. But now a new piece in The Atlantic is challenging the science behind that conventional wisdom, espoused by nosy aunts and OB/GYNs alike, and contends that there’s a dearth of meaningful studies about the effect of age on fertility. The ones that do hold water seem to indicate that the sharp drop-off in fertility does not occur until later than most women think.
Psychology researcher Jean Twenge knew that scientific studies are often oversimplified and misinterpreted in the media, so she decided to look into the studies that caused her own early-30s baby panic. She found that the oft-cited American Society for Reproductive Medicine statistic that one in three women 35 to 39 will not be able to get pregnant after a year is based on birth records more than 150 years old. Studies using more recent data find that the fertility rate of women in their late 20s/early 30s is only slightly higher than women in their late 30s. One study published in Fertility and Sterility found that 78 percent of 35-to-40-year-olds having sex during fertile times got pregnant within a year, compared with 84 percent of 20-to-34-year-olds. In other words, the idea that 35 is the cut-off for having kids without reproductive health might be total BS.
So how have women been this misled? One explanation is that fertility doctors make judgments based on what’s in front of them—and what’s in front of them are women desperate to get pregnant but having problems doing so. However, many of the fertility problems have been there all along, regardless of age, but only reveal themselves when the couple starts trying for a baby later in life, which likely makes doctors overestimate the effect of aging.
If you want to have children but aren’t sure you’re ready, how long can you wait? Only you can decide when the time feels right, but the latest studies—and more of the right kind of are needed—suggest that 40 is the age when fertility drops off in a dramatic way. The great majority of women in their late 30s, including the author, who now has three children, will be able to have children without reproductive help.
A version of this story originally appeared on iVillage.