How Your Friends Influence When You Start Family Planning

“Everyone’s doing it!” may not have been a valid excuse for hopping on trends in high school, but it seems to be enough to get women to think about babies post-graduation.

A new study published in the American Sociological Review found that women are more likely to have a baby after finding out their friends from high school are mothers, a trend researchers are calling “childhood contagion.” And no, this isn’t a pregnancy pact situation; the average age of a first-time mom in the study was 27.

“This research demonstrates that fertility decisions are not only influenced by individual characteristics and preferences, but also by the social network in which individuals are embedded,” says Nicoletta Balbo, a co-author of the study.

The data shows that once your friend has been a parent for a year, your likelihood of pregnancy nearly doubles. This “friend effect” only lasts for about three years, but that’s much longer than the one-year effect women seem to experience from siblings.

We’re not saying peer pressure should determine your reproductive choices, but the findings do make sense. You compare yourself with friends, learn from them, and share experiences with them. And when your best friend from calculus shows up to the ten year reunion with a bubbly, adorable 6-month-old, you start pining for one of your own.

“It’s also easier for people to remain friends when they are experiencing parenthood at the same time,” says Balbo.

The study is a testament to how much our high school friends can both affect us and stay with us.