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While we’re on the topic of gender bending animals, this chicken is half-hen and half-rooster. Epic.

Ed Yong wrote about it a couple of days ago, but apparently it was a very complex paper and I didn’t get his explanation. So without further ado, have some speculation from yours truly!

In humans, most of your cells are gender neutral. Sure, they’ll have the sex chromosomes in there, good old X and Y (or just XX if your a lady pirate like m’self). But those chromosomes don’t much matter to them. It’s hormones that control development. Pump in some female hormones and a man will grow lovely lady lumps. Pump male hormones into females and they’ll get a chestal region of the flat and hairy variety. Hormones hormones hormones.

Chickens are not people.

Chickens don’t have X’s and Y’s. They have Z’s and W’s, where ZZ=male and ZW=female. A bit like frogs, which are also a gender murky species imho.

In a chicken it matters what the cell is. If a chicken with ZW chromosomes is pumped full of male testosterone, it still looks like a hen. I think. That’s my understanding! Not to say that hormones have absolutely no effect, they’re still an important part of chicken life. They’re just not as important for defining gender when the chick goes through puberty.

The chicken above is the result of an experiment where they injected some female cells into a male embryo. One side ended up with more female cells and the other had more male cells. Voila.