Human Males: The Only Primate With a Big Penis

When it comes to a big penis, the human male stands alone. The human penis is, by far, the largest in proportion to body size compared to any other primate. A fully erect adult gorilla measures around 1.5 inches. Monkeys average just over 3 inches. Compare that to the human male, with an average penis size ranging from 5 to 7 inches, and the difference is undeniable.

What’s more, unlike many other species, the human penis doesn’t retract or remain hidden—it’s visibly present, as if it was designed to be on display. And maybe it was.

Women Notice Penis Size—Science Confirms It

A study published in the Proceedings of the National Academy of Sciences (PNAS) makes it clear: women are visually and sexually drawn to men with larger penises. Lead researcher Brian Mautz, from the University of Ottawa, stated plainly, “Penis size does influence attractiveness.”

Previous studies hinted at the same thing, but many were dismissed as biased or flawed. So Mautz and his team designed a new approach. Using advanced computer graphics, they created 49 lifelike male figures that varied in height, shoulder-to-hip ratio, and flaccid penis size.

These images were shown to 105 women between the ages of 18 and 35. The women were not told which traits were being tested. They were simply asked to rate each figure’s attractiveness as a sexual partner.

The Results Were Clear

Yes, women preferred tall men with broad shoulders and narrow hips—but penis size was nearly as important. The bigger the penis (in both length and girth), the more attractive the figure was rated. Women not only scored larger-penis figures higher—they also spent more time looking at them.

There were other patterns as well. Women with higher body mass indexes showed a stronger preference for large penises. Tall men with big penises received the highest attractiveness ratings, likely because a larger penis looks proportionate and impressive on a larger frame.

This Isn’t Just Cultural—It’s Evolutionary

Some argue that concern over penis size is a byproduct of porn and media. But researchers like Stuart Brody from the University of the West of Scotland disagree. He argues that this preference is rooted in evolution.

According to Brody, women make mate choices based on traits that signal reproductive fitness—penis size included. This fits with what the PNAS study uncovered: that larger penis size likely evolved through female mate selection.

What’s Size Got to Do with It? Vaginal Orgasms and Depth

A separate study out of Scotland looked at over 300 women. About half had vaginal orgasms in a typical month, and those who did reported a strong preference for deeper penetration. Not surprisingly, they also reported more orgasms than other women.

Mautz speculated that women may prefer larger penises not just for arousal, but for emotional bonding. His theory is that deep vaginal and cervical stimulation—only possible with sufficient size—floods the female brain with oxytocin, a hormone linked to pair bonding and trust. In other words, a larger penis may help create emotional attachment, which in turn benefits offspring survival.

The Oxytocin Theory: A Flawed Premise

Let’s be honest—this is where the theory falls apart.

To suggest that female orgasm, and the resulting oxytocin, is what kept large-penis males in pair bonds to raise children together is weak at best. A man with a visibly large penis in early human society wouldn’t need oxytocin or bonding hormones to keep him attached. He would have had access—to more women, more options, more power.

He would have been pursued, not clung to. The idea that this man would be more committed because he’s able to give women better orgasms defies logic. In fact, it’s likely the opposite. The men who could satisfy women easily had no need to commit. They didn’t need to settle—they had their pick.

So yes, women prefer bigger penises. Yes, it’s backed by science. But no, it wasn’t female orgasm or emotional bonding that kept the big men around. It was dominance, desirability, and the raw biological advantage of being able to give women what they couldn’t get elsewhere.

Orgasms Increases Conception

Why Big Penises Evolved: A Simpler, Biological Truth

Forget the oxytocin theory. The idea that female bonding hormones evolved the size of the human penis is not just weak—it’s based on emotion, not biology. The reality is much simpler: big penises likely evolved because they worked better.

A study published in Socioaffective Neuroscience & Psychology offers a more practical explanation. Researchers from University College Cork investigated the link between female orgasm and sperm retention. The sample was small—just six women, aged 26 to 52—but the findings were clear.

Over a two-month period, participants recorded self-induced orgasms at home under controlled conditions. For some sessions, women climaxed; for others, they didn’t. The timing was randomized. After each session, they inserted 5ml of a semen-like stimulant followed by a collection device designed to measure how much was retained.

The results? Women who had orgasms retained more of the semen stimulant. The researchers concluded: female orgasm appears to serve a sperm-retention function. In plain terms, orgasm may increase the chance of conception—by up to 15%.

So let’s connect the dots.

If female orgasm helps sperm stay inside the body longer, and bigger penises produce more orgasms, then it makes perfect evolutionary sense that men with larger penises would impregnate more women—and more effectively.

That’s not theory. That’s basic reproductive advantage.

A well-endowed male wouldn’t just be more desirable—he’d be more successful at passing on his genes. He’d give women better orgasms, and by doing so, boost the odds of conception. He wouldn’t need to form long-term bonds. He’d simply attract more mates and leave more offspring. That’s natural selection in action.

Compare this to the oxytocin hypothesis, which claims that larger penises evolved to help women bond with men emotionally. That theory assumes commitment, loyalty, and emotional attachment were the evolutionary drivers of penis growth. But in early human tribes, the man with the biggest, most satisfying penis wasn’t pairing off—he was spreading his genes far and wide.

It wasn’t emotional bonding that rewarded him—it was biological efficiency.

So let’s stop pretending the evolution of the human penis was about building families and hugging after sex. The truth is far less romantic: bigger penises caused more orgasms, more orgasms retained more sperm, and more sperm meant more babies.

That’s the real story. No oxytocin required.

Women Love the Package

Why Women Still Check Out the Package: A Primal Instinct That Won’t Die

In our primitive, nudist past, there was no mystery. A woman could easily tell which male carried the rod of ecstasy—and which one had the stub of disappointment. No second guessing, no awkward surprises. What you saw was what you got.

Fast forward to the 21st century. Clothes have made the game harder, but the instinct hasn’t gone anywhere. For the modern woman, every new encounter is like spinning the wheel on The Price Is Right. Is she walking away with a trip to Hawaii… or a goat and a rusty wheelbarrow?

The truth is, not knowing what a man is working with won’t stop women from trying to figure it out. And they try—more often than they admit.

You could say the modern invention of dick pics has brought us full circle—back to something primal in our evolutionary past. That’s why, in today’s world, it almost feels inevitable: once a man and a woman begin the dance of courtship, a photo of his “love rod” is likely to appear on her phone—whether she asked for it or not.

What Women Say (When They’re Being Honest)

Reddit users were asked a simple question: Do you ever look at a man’s package?
Here’s what some of them had to say:

Jacqueline George
“I’ve been in a few uncomfortable situations where I accidentally found myself looking in that direction. I zone out a lot, and sometimes a guy just drifts into my line of sight. Once in high school health class, the teacher ended up standing right in front of me. I didn’t even notice at first, but when I realized where my eyes were, I was mortified. Someone even called me out later. I swear I wasn’t trying to look—but yeah, it happened.”

Polly Young
“I look. Not all the time, but when the mood’s right or I find someone attractive, absolutely. It’s fun. I have an imagination. Tight jeans on men are lovely, in my opinion. Back when I was 13, my hormones were out of control, and I’d find myself staring constantly—bus stops, malls, wherever. I never said anything, but I definitely looked.”

Susan Nguyễn
“I had a friend in college who wore a specific pair of jeans that basically turned his crotch into a billboard. The fabric and wear patterns made it impossible not to notice. We laughed about it and called them his ‘look at my package pants.’ Even now, at 32, I catch myself looking if the guy’s outfit draws attention there—even if I don’t plan to act on it.”

A Poll That Says It All

A Reddit poll asked 64 women: What’s the first thing you check on a man?
The top two answers?

1. His package

2. His crotch

Even when they don’t admit it out loud, the eyes don’t lie. Women scan. Women notice. And often, it’s subconscious. The drive to assess a male’s reproductive fitness is buried deep in their wiring—and it’s been that way since we lived under open skies and wore nothing at all.

What Another 2001 Study Revealed About Penis Size and Female Preference

 A 2001 study published in the BMJ measured erect penis sizes and also gathered insights into how women perceive and prefer different sizes.

The study found the average erect penis length to be approximately 13.2 cm (5.2 inches). However, what stood out was how this size compared to women’s preferences. According to the data, a majority of women expressed a preference for a  larger-than-average penis, especially in the context of short-term sexual partners. The study noted that while emotional connection and other non-physical factors were important, physical attributes like size still played a role in attraction and satisfaction for many women.

These findings suggest that although most men fall within a normal size range, the desire to increase size isn’t just about insecurity—it may also be influenced by real-world preferences and expectations. This helps explain why many men pursue enhancement methods, from natural techniques to medical options.

Conclusion

Modern clothing might hide what nature used to put on display, but primal instincts don’t vanish just because we wear pants. Women still look, still assess, and still wonder what’s behind door number two. And whether it’s in a classroom, at the mall, or across a dinner table—some part of them is still trying to answer the oldest question of all:

Is he carrying a gift… or a letdown?