Are Men Really Biologically Wired to Want More No-Strings Sex?

Ask your neighborhood bro-scientist about his quest to plant half his chromosomes in every vagina in town, and they just might cite evolutionary biology. It seems there’s a narrative spreading around the internet that heterosexual men are biologically driven to “spread their seed”. Pointing to caveman days and sperm counts, some argue that men are designed to be non-monogamous and engage in much more casual sex than women.

I’ve even been told that genuinely non-misogynistic men reason that “science” is why sex on the first date makes them lose interest in pursuing a woman any further. There’s no judgment these days, they say, it’s just nature. The idea is men are designed to have relations with multiple women, since they can impregnate several women in a short time frame. But since women can only get pregnant once every nine months, they’re designed to be more monogamous than men. Others online (Andrew Tate sympathizers, surely?) go as far as to use this reasoning as an excuse for men cheating on their partners.

Setting the sexism aside for a moment – is there actually any truth to these claims about men’s biological need for sexual variety and women’s need for monogamy?

“That’s actually probably not the case,” says human behavior researcher Dr. Nathan Pipitone of Florida Gulf Coast University. After exploring men’s and women’s differing attitudes about casual sex in a recent study, published in the journal Frontiers in Psychology, Pipitone found that “on a surface level it looks that way, but digging deeper, it’s not that straightforward.”

His team asked hundreds of male and female college students to rate their willingness to engage in a variety of hypothetical casual hookup scenarios and compared their responses.

Each scenario went like this: You meet a potential partner at a party and you like them. If you hook up with them, it’d be sexually gratifying, and – cherry on top – there’d be zero risk of pregnancy. Plus, the person is either a 7/10 or 10/10 in attractiveness. The catch was the students had a chance of getting an STI. They then rated how likely they’d be to have sex with the hypothetical partner.

Pipitone found that the men were significantly more likely to engage in casual sex than women were. When their chance of contracting an STI was zero percent, about 80 percent of men and 50 percent of women in the study said they’d engage in the hookup. As the likelihood of STI transmission increased, the differences between genders decreased but persisted.

Pipitone’s study and the work of others seem to indicate that men are more opportunistic than women when it comes to casual sex. But don’t applaud bro-scientists just yet. Actual scientists say there may be sociological, rather than biological, reasons for this finding – namely stigma, sexual satisfaction differences, and inaccurate reporting.

Back in 2011, Teri Conley, a sexual health researcher from the University of Michigan, reasoned that straight women avoid casual sex not for lack of desire, but for fear of being judged. In her 2016 TED Talk, she cites research on sexual stigma, explaining that “women want respect out of a casual sex encounter, but they think that they’ll be called sluts. And surprise, surprise, women are stigmatized more than men for engaging in casual sex.”

Maybe this has something to do with the losing-interest-after-sex-on-first-date phenomenon after all? The stigma might appear to have improved in 2023, but it’s possible it’s just a lot more unconscious or covered up.

Then there’s the pleasure gap to consider. Conley and other experts claim heterosexual women may not be into casual sex as much as men because they tend to get less pleasure from it (shocker). Specifically, they don’t achieve orgasm as often, which some scientists refer to as the orgasm gap.

On average, men seem to orgasm 25 percent more during sex. The orgasm gap in college and university students is even more drastic, with a whopping 50 percent difference between men and women – the very same demographic that Pipitone’s study looked at.

To be fair, overall sexual satisfaction is slightly different. But still, research by sexual health expert Dr. Kristen Mark, of the University of Minnesota’s Medical School, shows that on average women often don’t experience as much sexual and emotional pleasure from sex as men do, either.

Putting her findings into context with the spread-the-seed debate, Mark argues: “We know that if you’re experiencing pleasurable sex, you’re more likely to want that sex. And who’s experiencing the most pleasurable sex from casual encounters? Well, our research shows that men are. Women aren’t really getting a lot of pleasure out of casual sex because, well, the patriarchy.”

Perhaps this is why women tend to seek out less casual sex than men do. But Pipitone and his team attempted to account for this by telling the students the sex would be gratifying. Maybe the promise of an orgasm is just too good to be true for a 19-year-old woman?

Beyond that, inaccurate reporting may play into the finding that men want more casual sex than women. “In terms of reporting the amount of short-term sex had, women probably don’t report cheating or non-monogamous sex encounters as freely as men, and men are probably more prone to exaggerate it,” continues Pipitone. “Heterosexual men report more sexual encounters and partners than women do, but who are these men having sex with? They’re having sex with women.”

According to the Centers for Diseases and Control and Prevention, American men and women aged 25 to 49 (who’ve had sexual relations with the opposite sex) report an average of 4.3 and 6.3 opposite-sex partners over their lifetime, respectively. Apart from this surely feeling like a huge under-exaggeration, something’s not quite adding up, as Pipitone says. In the UK, the male-female reporting gap persists, with men reporting five partners and women reporting three, on average.

If we imagine the findings are indeed accurate – AKA men are more motivated to have casual sex than women are, regardless of any mysterious forces that could be repelling women from going all the way – does evolutionary biology support the idea?

Pipitone says that yes, there are evolutionary explanations for why men would go for casual sex more than women would: “Women have more to lose if sex leads to a pregnancy she doesn’t want.” Along with the huge bodily effort, undesirable partners of unplanned pregnancies would’ve been (and still are) a huge problem, which is why he feels “women are more discerning with who they have sex with”.

But this doesn’t mean women are programmed to avoid casual sex entirely. Remember, in Pipitone’s hypothetical hookup study, 50 percent of them said they’d agree to have casual sex – not accounting for any under-reporting.

There are reasons casual sex could evolutionarily benefit women too, Pipitone explains, which crumbles the audacious proclamation that women are biologically driven to steer clear of no-strings-attached sex.

“There are various adaptive reasons why women would engage in short-term sex encounters,” he says. “Some include mate switching, or mate expulsion, meaning getting out of a bad relationship.” Then there’s “mate competition,” which sounds a lot like what it is – determining which suitor wants to commit the most.

Within mate switching lies a contentious portion of the “good genes hypothesis”: The idea that women might sample sperm, so to speak, from new partners with advantageous genes, to increase the genetic diversity and fitness of their offspring. The idea is the women would pretend the baby was from their long term partner, but really, they got pregnant from someone else. Of course, this line of thinking doesn’t pair too well with the invention of the paternity test, so maybe mate switching looks slightly different in 2023.

Rates of non-paternity (AKA when the man who thinks he’s the father isn’t actually the father) in the research have ranged from one percent to 20 percent depending on the geographical area examined, Pipitone says. “So this tells us that there are adaptive, good-for-your-genes benefits not only for forming long-term pair bonds but also for moving outside of long-term relationships, for both men and women.”

On the subject of monogamy, Pipitone says it was an important part of our development as a species: “We still see monogamy and biparental care now because it was super important for humans throughout our recent evolutionary history. It probably coincided with the increases in brain size which started about two million years ago.” Unlike other animals, human babies are pretty helpless. Monogamy and biparental care means more eyes on the babies.

Regardless, that doesn’t rule out both sexes’ tendencies for the occasional bout of infidelity – especially with the introduction of birth control. “We’re more like serial monogamists, forming several longer pair bonds throughout life, with a dash of polygamy thrown in, including infidelity,” adds Pipitone.

So back to our big questions – if women are just under-reporting how much casual sex they would have, are having, or desire to have, are the genders’ biological drives for sex so different after all?

Maybe, but we don’t know for sure. What we do know is that, for now, whether it’s due to societal norms or evolution, straight women at least say “they’re gonna be more selective in their mates and maybe have fewer mates compared to males,” says Pipitone. “This shouldn’t be taken to mean that women don’t want casual sex, or that they’re less sexual than men, though. Female sexuality just manifests differently.”

All in all, here’s one point for bro scientists: There are actually evolutionary reasons men would be driven to have casual sex or engage in infidelity.

But here’s what they’re missing: There are evolutionary reasons women would, too. We just may not be seeing much evidence in our day-to-day lives, perhaps because of stigma and their slim odds of feeling satisfied by sex.

So next time this topic comes up, tell your neighborhood bro-scientist to put that in their sexually unsatisfying pipe and smoke it.