There are some questions in life that you’re better off not knowing the answer to – like how hot dogs are made, or what’s really in beef jerky. But if you often wonder, “Why are penises shaped the way they are?” you deserve an explanation.
Before we get to that explanation, it’s worth noting that there are a lot of different penis shapes out there. Similarly to vaginas, there are many types of penises that look different from each other. Some may be mushroom-shaped, others may be circular or oval-shaped. If your penis or your partner’s penis doesn’t look exactly like what you’ve seen before, that doesn’t mean there’s something wrong with the way their penis looks. It’s just simply a different shape and style. After all, as we know by now, penis size and shape is largely related to genetics.
But for those of you who are still curious about why penises are shaped the way they are, trust, the answer is way more unhinged than you probably think.
Experts Featured in This Article
Anika Ackerman, MD, is a New Jersey-based urologist.
Sarah Melancon, PhD, is a sex researcher and sex expert at Sex Toy Collective.
Daniel Boyer, MD, is a medical researcher with a focus on molecular biology, histology, pharmacology, internal medicine, gynecology, and obstetrics.
Why Are Penises Shaped the Way They Are?
According to evolutionary theories, some penises are shaped with their signature mushroom-like head because of what’s called the semen displacement hypothesis. This hypothesis suggests the mushroom shape can scoop out other men’s semen from the vagina. (Yes, you read that right.)
It’s all based on the idea that men ultimately want to be the one to impregnate their partner and that being able to scoop out other men’s semen during sex with their in-and-out thrusts increases that likelihood.
New Jersey-based urologist Anika Ackerman, MD, says that the semen displacement theory is a result of “evolution and male competition” and was studied by researchers in 2003. The researchers used a silicone vagina and a latex penis to mimic intercourse. They were able to prove that “the shape of the penis allowed it to scoop out a semen-like substance,” Dr. Ackerman says. She adds that 90 percent of the cornstarch and water mixture (the makeshift semen) was removed with just one thrust.
Dr. Ackerman says this study validated the displacement theory since it proved a man’s coronal ridge (aka the head of the penis that shapes into the mushroom) would drag out other men’s semen and allow their own to remain when they’re finished.
Though this may be hard to believe, and honestly, it just sounds like misogynistic BS, sex researcher Sarah Melancon, PhD, says it’s a real evolutionary theory. But it’s not rooted in 100 percent fact. She explains that there are loopholes, especially when you look at how the body ovulates: “Sperm can live up to five days protected by cervical mucus. Otherwise, the vagina is highly acidic and sperm will die within hours.” With that in mind, “semen displacement would therefore only be an issue if a female is having sex with multiple men within a period of hours or during ovulation,” she says.
Personally, I’d like to think penises are mushroom shaped in a years-long effort to create pleasurable sensations for both men and women during sex. Daniel Boyer, MD, agrees: “The shape is primarily a physical adaptation to increase efficiency and facilitate successful mating.” The mushroom aesthetic also gives the penis a more appealing look. It makes it less “Hey, look at this long thing” and more “Look at this thing that vaguely resembles a food that could have you tripping in no time.”
So regardless of what method or theory you believe or what you do with this information, you now have all the information you need to bring it up at happy hour with your friends. Enjoy.
Taylor Andrews is a Balance editor at POPSUGAR who specializes in topics relating to sex, relationships, dating, sexual health, mental health, and more. In her six years working in editorial, she’s written about how semen is digested, why sex aftercare is the move, and how the overturn of Roe killed situationships.
