TIME

6 Weird Scientific Facts About Love

Bride and groom couple
Cultura RM/Mallon Industries—Getty Images/Collection Mix: Subjects RM

Sure, you know the basics about the birds and the bees, but how much do you really know about what goes on in your body—and your mind—while you’re falling head over heels or doing the deed? Here are some fascinating facts about love and sex that may surprise you.

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Spouses may have similar DNA

Scientists already knew that people tend to choose romantic partners with similar characteristics, such as age, race, religion, income, and upbringings. But a study published in the Proceedings of the National Academy of Science found that people also tend to marry others with similar DNA. When researchers studied the genetic material of 825 white American couples, they found fewer differences in the DNA between married people than between two randomly selected individuals within the same race. In fact, they calculated that the tendency to pair up with a genetically similar spouse is about one-third as strong as the tendency to do so with someone with a similar education.

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Watching rom-coms may help strengthen marriage

Watching movies may be one key to marital bliss, says Matthew Johnson, PhD, director of the Marriage and Family Studies Laboratory at Binghamton University. In his study, couples attended counseling or watched relationship-themed movies and completed discussion guides together. Both strategies cut the groups’ divorce rate in half after three years—but the movie-watching activity took 50% less time and took place almost entirely at home. “The key is to talk with your partner about your relationship in the context of a movie,” says Johnson.

Women can make their voice “sexier,” but men can’t

In a 2014 study, Albright University researchers found that women were able to deliberately manipulate their voices—while counting from one to 10—to sound more attractive. But, sorry guys: When men tried to be sexier, they were actually rated as sounding worse! When a woman intentionally drops her voice to make it sound low and breathy, she’s often perceived as more attractive—but not exactly for the reasons you might think. Men tend to prefer women with higher, more feminine voices, says co-author Susan Hughes, PhD, associate professor of psychology. But when a woman lowers her voice to “sound sexy,” she’s signaling her interest in a potential mate—a clue that men are able to pick up on.

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You’re less likely to get grossed out when aroused

Sex can be a messy activity with lots of fluids and smells, but in the heat of the moment, none of that (usually) seems to matter. According to a study from the University of Groningen in the Netherlands, that’s because sexual arousal overrides the body’s natural “disgust response.” When researchers asked women to watch either an erotic film, a sports video, or a “neutral” video of a train, and then perform a series of unpleasant acts (like drinking out of a cup with a bug in it), they found that those who’d watched the sexual acts rated the tasks as less disgusting—and were also able to complete more of them. Previous research has suggested that sexual arousal has a similar impact on men, as well.

Love is good for your bones

Marriage appears to strengthen men’s skeletons, according to a University of California Los Angeles study, especially if they wait until after age 25 to tie the knot. Researchers aren’t sure why, but they point out that it’s not the first time marriage has been linked to health. Other studies, for example, have suggested that married people live longer, are more likely to survive cancer, and have a lower risk of cardiovascular disease.

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Old people do it, too

Sexual interest and sexual function do both decline with age—especially as adults begin to take more medications—but that doesn’t mean that senior citizens aren’t still getting it on. “Many people do continue to have sex into their old age, often until death,” Garcia says. And they’re not always careful: “Besides teenagers and young adults, the elderly is the biggest population for sexually-transmitted disease spikes,” he adds. “They’re not worried about getting pregnant, so they’re not using condoms.”

READ MORE: 20 Weird Facts About Sex and Love on Health.com

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