Why are testicles so sensitive?

It appears to be common knowledge that a man’s testicles are extremely sensitive. A kick in that region will cause extreme pain.

2 questions:

Why is this particular body part so sensitive?


Is here some lasting overall damage done apart from the pain?
(smart-ass answer shield up)

"Unlike most other parts of your body, though, your scrotum lacks protection in the form of bones, large muscle mass, and fat. The testes are just wee little glands, and they’re going to absorb the whole force of the blow all on their own.

Another thing that makes a ball shot so painful is the same thing that makes almost every other sensation down there so much fun. Your groin has a ridiculously high number of sensory nerve endings, and such generous innervation makes good and bad touches alike very noticeable sensations."

But seriously Bardos when was the last time this happened to you? What went wrong?

If you damaged your gonads to the point that you could not reproduce, then that’s you out of the genepool (unless you had previously reproduced). Natural selection would strongly favour those who have heavily innervated gonads. Particularly for bipedal species, where they are less protected.

(Note: for some kinds of dangerous stimuli a knee-jerk style response could be evolved instead of pain. But there is no simple knee-jerk response appropriate to defending the nuts)

One thing to be aware of however is that there are different kinds of nerves for sensory touch and pain. It doesn’t follow that because an organ is sensitive to touch that it must be sensitive to pain.

Can’t speak for Bardos, but it happens (though not usually as a kick, at least not for me). I’ve been whomped in the crotch by a soccer ball and a raqcuetball before. More recently I borrowed a friend’s motorcycle; I was unfamiliar with the shape of his particular bike, so when I settled down in the saddle, I inadvertently crushed my grapes against the fuel tank.

I have to imagine that if you could reach in and thwack any other internal organ with the same amount of force, it would hurt just as bad. But if you were in a situation where your kidneys were hanging out of your body like that, their sensitivity would probably not be your largest concern.

Actually the real question should be, “Why are your incredibly sensitive nuts hanging outside in the first place?”

I seem to remember that it has something to do with temperature requirements for sperm production. Cooler temps make for the production of more sperm.

So the boys hang free hoping to catch a breeze.

Sexual selection might have played a role there too.

**Why are testicles so sensitive? **

Because they get teased a lot.

you have lots of small tubes and ducts to have that whole thing function. lots of blood vessels and material moving mechanisms.

damage can render part or all of that apparatus nonfunctional. could also involve long term discomfort events too.

You mean like the knee-jerk response I get while reading a thread about getting whomped in the nuts?

They have to be outside the body so the little swimmers don’t die off from body heat, however, nature put them between the thighs… in a location where they get some protection. My 2 cents.

It’s to allow sperm temps to be regulated. That’s why they shrivel up when you get cold. So they can be closer to the body and thus warmer. Or hang low when you are hot.

High internal body temperature doesn’t seem to be a problem for egg cells. What makes the sperm different?

There may be a question here of whether testicles are particularly sensitive as a means of warning their owners of the need to protect them.

Maybe they are sensitive so that males will want to have sex, i.e. sensitive = pleasure. Otherwise males would just drink beer and watch sports all day and the species would die off.

I’ve been babysitting for the past year or so and discovered that a 6 year old’s testicles aren’t sensitive at all. There is all manner of crotch punching going on at the playground and he says it doesn’t hurt. Is this normal? At what age do they become sensitive?

The “testicles are outside the body for temp control reasons” argument may not be accurate. I recently read (I think it was in Mary Roach’s Bonk, but it could have been a magazine article) that while testicles outside the body (TOB) have evolved twice in mammalian lineage, there are mammals which keep their testicles inside the body (TIB). TIB mammals produce sperm at body temp with no problems at all. There were also, IIRC, a couple of species which had changed from TOB to TIB and had no ill effects.

The downside is that it’s looking more and more like TOB is a form of sexual selection. So, TOB are the equivalent of peacock tails and stag antlers. Look out, gentlemen. In another 10,000 generations, you may be dragging your testicles on the ground.

Well, why does pain exist at all, other than as a means of warning / deterring the organism?

Again though, there are different kinds of nerves and there is no reason why our gonads could not be very sensitive to touch but quite insensitive to pain (and in fact there are different kinds of nociceptors, so a tissue could be sensitive to, say, hot and cold, but not blunt trauma).

In humans we only really have good examples of organs that are sensitive to one or more forms of pain and insensitive to touch, but not the other way round. But anyway the two things are not coupled.

It’s not always that much pain. In many situations you won’t feel pain at all from physical harm such as a sharp blow. Martial artists say they can tolerate the pain of a low blow but I’ve never heard one say they don’t feel it.