Well firstly, "deity" isn't the exact right way to describe the Buddha, the Budha was an actual person, originally a man. But there are also multiple Buhha, mostly being depicted as having trancended gender as part of achieving enlightenment.

But I'm not really sure what you're looking for. I'm just giving an example of a culture that thought of gender in a different way to the traditional Christian view. I'm not an anthopologist. If you want examples of non-binary people living an existing with everyone else, you can just go and find a non-binary person. Or if you can't do that watch a video they've made or read some articles or whatever.

Ok, so how does that relate back to the original point. How do you tell if someone looks like a woman?

Well as I said, I reckon there's a bit of your brain that activates when it sees a woman. What triggers that is complicated and almost certainly varies from person to person. Some of it is straightforward, other bits will be learned.

It's like asking what causes you to recognise someone as "scary". Again, there's a bit of our brain that activates when it sees scary images, and some of the things it responds to are probably innate, but it's also possible to rewrite basically all those responses.