1. People are most likely to conceive a child in December.
According to one study, that’s when kids born in the US are most likely to be conceived — around 9% of American babies were conceived in December. One possible reason, as the study authors sexily put it: “Increased sexual activity associated with end-of-year holiday festivities has […] been postulated.”
2. But people also stockpile condoms before Christmas.
Another study shows that twice as many condoms are sold the week before Christmas than the week after. So at least some people are trying not to get pregnant around the holidays. Also, Christmas condoms exist (see above).
3. The fewest conceptions happen in August.
But not necessarily because no one is having sex. Scientists think summer heat might hurt sperm, and that seasonal changes could affect female fertility too — the length of the day may have an impact on ovary function.
4. People search for the most porn at Christmastime and in early summer.
A study found that Google searches for terms like “porn,” “boobs,” “xxx,” “call girl,” and “massage parlor” peaked in early summer and around the winter holidays. Google searches for “eHarmony” and “Match.com” also peaked around these times, suggesting that people were looking for love as well as sex, and that they did not understand how to work a web browser.
5. That may also be when people have the most sex.
A 2007 review of existing research found evidence of sex peaks in early summer and around Christmas — researchers call these the “holiday season effect” and “summer vacation effect.” One psychologist, Diana Kirschner, thinks just the memory of summer vacations past makes people want to have sex: “We were raised in the rhythm of a school calendar for […] the first 20 years of our lives. Summertime meant party time — which means we are conditioned to relax, let loose, and have more fun in the summer, [including] sex.”
6. The rest of the winter may bring a drop in libido.
Holiday season aside, some researchers think people’s sex drive is weaker in winter. One study found that testosterone (which can boost libido in both men and women) was lowest in winter and early spring, while other scientists think people’s sex drive may drop in winter because that’s when their animal ancestors hibernated. However, there’s considerable debate on this point — another study found testosterone was actually lowest in summer.
7. But men find women hottest in winter.
Their bodies, anyway. In one Polish study, men rated pictures of women’s breasts and bodies as more attractive in the winter than in other seasons, but they rated pictures of women’s faces the same. The study authors think the cause may be women’s winter clothing: men don’t get to see women’s bodies as much during the winter, so they’re more excited when they do.