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Holidays

There's an annual post-holiday baby boom 9 months after Christmas

Internet searches for 'sex' hit a peak during the holiday season, which corresponds to a global increase in birth rates come the following September, according to a new study.

Between putting that perfect present underneath the tree, sipping tasty winter cocktails, and popping bottles of bubbly on New Year's Eve, everybody knows the holiday season is the happiest time of the year. (At least it's supposed to be.)

The holidays also happen to be the time of year when people are having a lot of sex—and are most likely to get pregnant.

Online interest in sex peaks around the world during major religious or cultural celebrations (like Christmas), which corresponds to increased births nine months laters, according to a new study published in the journal Scientific Reports.

In the study, researchers used data from roughly 130 countries that included sex-related Google search terms between 2004 and 2014, and a portion of public Twitter posts from 2010 to 2014. They then matched this data to birth rate trends from that time frame to conclude that there is a direct relationship between the spike in search terms and the subsequent births.

Why does this happen? Researchers also did a survey of key words in Twitter posts (called a "sentiment analysis") during the holidays, and found that, generally speaking, people feel happier, safer, and calmer during these special times of the year, and therefore more likely to get it on.

"Perhaps people feel a greater motivation to grow their families during holidays when the emphasis is on love and gift-giving to children," says Luis M. Rocha, a co-author on the study. And while some couples might focus on adding a plus-one to their family over the winter break, singles are doing just the opposite—but that doesn't mean they're not having sex. More than 60% of young singles are likely to have casual sex when they're home for the holidays, according to this study from Trojan Brand Condoms.