Health

Why Some Men Are Attracted to Pregnant Women, According to Science

Sexual imprinting explains why being hot for your pregnant wife is your younger sibling's fault.

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a shirtless man kisses the baby bump of a pregnant woman in a bra and underwear who is laying down

Pregnant women are a turn-on for some men, and sexual imprinting may offer an uncomfortable explanation for this phenomenon. Sexual imprinting is how animals learn to choose suitable mates, usually by observing their parents at a tender age. In humans, scientists suspect that babies learn sexual preferences (and perhaps even fetishes) predominantly from their mothers. And if mom is pregnant, pregnancy is attractive.

“Babies predominantly imprint on their caregivers, and mostly the mother — either because they spend more time with her or because of some biological trigger for imprinting, such as breastfeeding,” says Stefano Ghirlanda, PhD, a psychology professor at Brooklyn College. “If your mother is pregnant during the imprinting period, you may build an image of the ‘perfect partner’ that contains these characteristics.”

In a study on this very subject, Ghirlanda notes that there are ample examples of sexual imprinting in animals. Goats who were raised by sheep mothers tend to only be sexually responsive to sheep. A giant panda once famously refused to mate with another panda but propositioned a zookeeper. Sexual imprinting in humans is more controversial because the human brain is still not well-understood.

“The difficult part is that no one really knows how the biology works, which parts of the brain are involved, what decides which memories are stored, what decides which sex becomes attractive to a given individual, and so on,” Ghirlanda says.

For this study, Ghirlanda and colleagues recruited 2,082 people from pregnancy and lactation fetish online groups. Participants were asked about their sexual preferences (most reported being into both pregnancy and lactation), as well as the age and sex of each of their siblings. They found that having a younger sibling, and extensive exposure to their mother before age 5, was significantly linked to a sexual attraction to pregnant and breastfeeding women. This pattern held for women attracted to pregnant women, too.

One implication of these findings is that older siblings who spend a lot of time around their mothers may sexually imprint on women who are likely pregnant and breastfeeding. But the study is far from definitive and more of a small step toward understanding how sexual preferences and fetishes arise in humans. Ghirlanda hopes his study will help increase acceptance of harmless sexual preferences.

“It is something that can happen naturally and is not a symptom of any illness,” Ghirlanda says. “Any peculiar sexual preference is a problem or not, depending on whether it is accepted by society. Same thing, I believe, for pregnancy preferences.”

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