Sometimes, evolution is all sorts of messed up.

Some humans like to view evolution as an almost spiritual driving force. After all, evolution has turned us into complex, intelligent beings with large brains and opposable thumbs. It’s been kind to us. Evolution quite literally has brought us to a higher level.

It’s no surprise we think of evolution as infallible—we evolve advantageous traits that help us survive and rule over an unforgiving world.

But that’s not always the case. The human body is not perfect—far from it, really. In fact, our bodies are full of design flaws, proving evolution can be a sticky and seemingly random process with no clear blueprint in mind. We’ve even evolved traits that are disadvantageous!

In an Ask Reddit thread user Breeze_in_the_Trees posed this question to the Reddit community: “Human anatomy: What would you redesign?”

Here’s what the Reddit community said.

Testicles

I’m not sure balls look sad. In fact, I think they look quite cheerful, but it is pretty strange that most mammals have evolved external testicles in the first place. Anyone who has been kicked in the nuts knows that external testicles are incredibly vulnerable and defenseless to predators.

As paleontologist Matt Borths told Upvoted in an article about, yes. dinosaur testicles: “Mammals are the only animals that have taken the apparently idiotic evolutionary step to let half the genetic diversity of future generations hang out in the wind.”

We don’t know why humans have external testicles. It may have to due with sperm production, but we aren’t sure. It would make more sense if testicles were tucked away inside the body—like in elephants.

Arms

Hearts

Most cephalopods (octopuses and squids) have three hearts. Do they need a TARDIS? That remains to be seen.

The Prostate

Scientists are unsure why the male urethra directly goes through the prostate instead of around it. When men become older, their prostate naturally starts to enlarge. This usually happens around the age of 40. Sometimes the prostate will become so big that it will strangle the urethra, preventing men from being able to pee, according to biologist Lewis Held’s Quirks of Human Anatomy. Ouch.

Gills

Actually, human embryos do have gills (or branchial arches) in the womb, which eventually develops into structures that form our face. Gills are vestigial traits left over from our aquatic ancestors.

The problem is, humans can’t survive long periods without oxygen (we start to exhibit brain damage after four minutes in most cases). Other animals, like turtles, can hold their breath for three hours, wrote Held.

Ears

Some people have strange tastes, I guess. This can’t really be explained.

The Vagina

Speaking of which:

Waste and sex organs

Our anus and genitals are way too close together, making it incredibly easy for fecal bacteria to infest your vagina or penis. This is what causes urinary tract infections (UTIs). Although this distance between the urethra and anus is shorter in women, men can still suffer from UTIs.

Skin

Photosynthesis?

Some people have, um, active imaginations.

For more quirky human redesign suggestions read the entire thread here.