Weird Sex Science Fact of the Week: Why Balls are Crooked and Penises Hang Left

So you love someone with male genitals, or own a pair yourself, and have been wondering wtf up with balls? Why does one hang lower? And what up with the penis dangling to the left when limp?

All over the Internet, men leave questions expressing fear and anxiety about perfectly normal variations in their genitals, including why their penis hangs on one side to why their testicles are uneven in size.

The reality is that assymmetry in male genitals is normality, not deformity.




About 75% of all cis-men have penises that naturally hang to the left. According to the journal, Human Reproduction, the left-dangle likely means that the man is left-brain dominant. The left brain controls logic/mathy functions, while the right brain is considered the more creative, visual side. So, as Men’s Health once put it, “if your penis dangles to the left, that could help explain why you’re great at algebra but crappy at guessing your girlfriend’s mood.”

If you hang to the right, that’s fine too. Just as left-brain dominant people hang to the left, right-brain dominant ones hang to the right. Meanwhile, about 8% of men dangle straight down and can dress left or right.

All that said, some scholars speculate that personal habits may influence it too: if you were taught to tuck left or right, your penis may eventually naturally fall in that direction. And here you thought your penis had a mind of its own, right?

(Aside: “Dressing” is an old term for which side of your pants you wear your penis on. In the days of custom-tailored clothing, an elegant outfitter would ask you how you “dress” before cutting your pants so they could leave a little room for your penis to fit in discreetly either left or right. A few years ago, some UK entrepreneurs ran a Kickstarter in hopes of making new underwear designed to fit left-leaning men. Hilarious, but practical too! Here’s a link to their inspired but expired campaign for “Cahoonas.”)


Assymmetry in male genitals is normality, not deformity.



The clinical term for the the naturally uneven development of balls is testicular asymmetry, and it is all part of nature’s plan. Roughly 65% of all men naturally have a smaller (7-10% smaller) left ball. The smaller testicle hangs lower than the larger one on the right, which confuses people who imagine the bigger one should hang lower. But this isn’t about gravity, it’s about male sexual development from the time you’re a fetus.

The scientific explanation on how how it happens is that the right testicle grows faster when males are still in their mothers’ wombs, thus explaining why they are born with the right one usually larger than the left. Also, strong muscles on the right side of the abdomen indirectly give the right testicle an extra lift by pulling the testicular cord upward.

We are less certain about WHY it happens and whether asymmetry brings any evolutionary or reproductive advantages. An obvious theory is that the unequal size/hang helps avoid them banging into each other. CLANK! Awkward.

More speculatively, evolutionary biologists have theorized that the asymmetry exists to regulate scrotal temperature, keeping your balls cooler and your sperm healthier.




Empty Sac = Undescended Testicle

Some men may discover that the asymmetry far exceeds the 7-10% mentioned above. BIG RED FLAG if you don’t feel a testicle in one of the sacs. In most cases, a doctor will quickly catch the problem in childhood. But if you or someone you love never received assessment of your scrotal health, please be aware of this condition.

Early in the life-cycle of men, their testicles “drop” from the safety of their abdominal cavity where they originally grew. They descend into the scrotal sac, one ball on each side. Undescended testicles are a fairly common medical problem in newborns. By the time they hit puberty, only one in 50 boys still has the issue (one or both balls have not descended). By adulthood, only 1 in 500 cis-males still have a testicle in their abdominal cavity instead of their scrotum.

The risks of going through life with an undescended testicle include higher chance of testicular cancer, hernias in the groin and a medical condition that sounds as painful as it is. Testicular torsion happens when the cord connecting your balls to your body twists up and strangles off blood circulation to your balls. Can we say SAFE WORD!!??

Men with undescended testicles need to consult with a urologist on treatment options to avoid such miseries.


Sudden Change in Testicle Size or Shape

Another time to worry is if there is a significant difference in size. If one of your balls is lumpy, changes shape or texture, or grows much larger than before, you need to see a doctor immediately for a formal diagnosis. It could be an early sign of cancer.

Whether or not you’re worried you’re at risk, it’s good protocol to give yourself routine self-examinations to make sure all parts stay in good working order. Follow this helpful guide to learn how to do a testicular self-examination and find out what warning signs to look for.



Just as our faces are asymmetrical (with left side and right side looking different when separated), just as women’s breasts are asymmetrical (roughly 65% of women have one breast larger than the other), the male body has built-in asymmetry. We’re still not sure exactly why we have evolved this way but, clearly, it works! 🙂 So enjoy the beautifully complex body you have and quit worrying.