When I called Benjamin Brucker, M.D, assistant professor of Urology at NYU Langone Medical Center, to talk about penises, he had a lot to say. "I'm happy that I found someone as interested in the male phallus as I am," he told me, enthusiastically. And then he proceeded to tell me everything there is to know about penises. Here are the 10 penis facts everyone handling penises should know:
1. There's really no difference between circumcised and uncircumcised penises.
The only discernable difference between circumcised and uncircumcised penises is the likelihood of developing penile cancer (it's rare in general, but uncircumcised men are at a higher risk). Uncircumcised men are also slightly more likely to transmit HPV and HIV to partners if they don't use a condom.
Those bummers aside, most of the assumptions people have about circumcision affecting penis size and sexual prowess are myths. "Being uncircumcised really should not affect the size of the penis; it's just the appearance," says Dr. Brucker. "It's probably not something they really notice, per se. The foreskin probably pulls back a bit during vaginal penetration and so I don't know if there's anything they would necessarily notice." It's really just personal preference: Do you prefer your convertibles with the hood up or down?
2. Penises can break.
"It's called a penile fracture. You would think of a bone fracturing because that's what most fractures are described as, but the fracture in the penis comes from the fibrous tissue of the penis essentially developing a rip or a tear in it," says Dr. Brucker. Because we all know the penis is not a bone or a muscle, but an organ, right?! Right! "Sometimes in medical textbooks they'll call [a broken penis] an 'eggplant deformity' or an 'eggplant' because it will actually turn purple, bruised, and take on that shape of an eggplant." Every man reading this just swore off eating eggplants forever.
3. But they're pretty resilient.
It might be easy to do some damage to a penis with an errant tooth or an overzealous grip, but don't worry about doing any permanent damage. Going limp is the penis'natural reaction if a guy is in any kind of pain (to avoid becoming an eggplant). "The good news about the penis is that it has a lot of blood flow in most men, so it heals well and allows your immune system to work," said Dr. Brucker, "but just like any other part of your body it needs to be treated appropriately and you don't want to be too aggressive."
4. Men can get yeast infections and UTIs too.
Typically, you're not going to pass on yeast infections or UTIs to your partner, although it can happen. "A female urethra is usually about four centimeters and the man's urethra is longer. Some guys can get topical yeast infections; it's usually just a skin irritation. When a man gets a urinary tract infection, there's usually a problem going on, like an enlarged prostate," explains Dr. Brucker.
5. Erectile dysfunction is usually indicative of other health issues.
"There's a whole category called 'psychogenic erectile dysfunction.' So let's say a man had an affair and he goes back to have sex with his wife. Things don't feel the same and he has difficult time getting an erection," says Dr. Brucker. That doesn't mean every man with ED is a cheater. Stress, drugs (prescription or otherwise), alcohol, age, and obesity can all cause ED. Erectile dysfunction can even be a sign of diabetes or heart disease. "Once you start to see erectile dysfunction, the first thing you should evaluate is his overall health."
6. No one actually knows the average penis size.
There's no standard tool for measuring a penis and no easy way of doing so. Some studies stretch the penis out by tying a weight to it (oy), others measure from the base of the pre-pubic area as opposed to the base of the penis. And penises are always changing size. "A large portion of the penis is actually inside of the body and then there's also the distinction between when you're measuring the penis of a man who has a little bit of weight in the pubic hair area or not. You can have a guy with the actual same penis length and he's super skinny — the portion of the penis measured may appear to be longer versus a guy with a little weight on him."
7. The clitoris is basically a tiny penis.
"In embryologic development, the penis and the clitoris actually evolve from the same tissue. So the clitoris can technically become erect," explains Dr. Brucker. Basically, everyone starts with vaginal lips in the womb, and if the Y chromosome is present, things start flipping around like a genital Transformer. "The ovaries, or the gonads, descend and become the testicles, the labia fuse and become the scrotum, and then the clitoris enlarges and becomes the penis." Wild.
8. There's really no scientific basis for the idea of a guy being a "grower not a shower."
Every penis is different. "You can have a man with a small penis who gets erections and is large, or a man with a small penis who gets erect and it doesn't grow more, or you can have a man with a large penis who gets erect but it doesn't grow anymore. Or you can have a man with a large penis who gets erect and it grows more," says Dr. Brucker. Judge not ye the penis that neither grows nor shows.
9. Only being able to have sex for two minutes isn't really premature ejaculation.
"Men think they're supposed to be able to last an hour and a half or two hours, but the reality is most women would say at that point sex becomes uncomfortable. Most of the time sex lasts minutes, not hours," says Dr. Brucker. The average guy lasts about five minutes.
10. Men can't always get erections back-to-back because their penises basically just ran a marathon.
Every penis is different. Some can do back-to-back sex sessions, and others need to take a break and rehydrate. It's what's known as a refractory period. "The refractory period is just part of normal physiology. Different parts of your nervous system are working for erections and ejaculation, and it's hard for your body to switch back and forth quickly. The refractory time varies a lot based on age and other issues," says Dr. Brucker. Don't be disappointed if the penis needs a break every once in a while. It's just extra time for him to go down on you or try something new.
This article originally appeared on Cosmopolitan.com. Minor edits have been made by the Cosmo.ph editors.