The ironic thing is that in modern society, I feel like we should not treat people of differently based on sex/gender. The only time it really crosses my mind as a male, is that if there is a violent altercation or self-defense situation, you should never strike a female, and you should try to protect a female if they can't defend themselves. But this is generally because they are probably physcially weaker...unless they are an MMA fighter or something.

Especially in the workplace, and especially when working on the internet. It would be wrong to treat someone differently based on sex/gender. Which is why all the gender pronoun insistence is a bit strange.

The only other time is to do with romantic relationships or sexual interest.

An interesting question is what about women interests men, and is it environmental vs innate?

I think its clear that innately men are interested in roughly the same physical characteristics of women.

But for the societal adjectives/behaviours used to describe "femininity"...are these innate to females? Or do women simply fit the stereotypes that were universally desireable for men innately? Or are these feminine stereotypes (or male's female behavioural preferences) a relic passed down from past societies.

As a hetero male, it's interesting to think about why you are interested in women. Your first girlfriend, why were you interested in her. And before you were even old enough to be interested in sex. For me, if I recall it was extremely innate. The shape of their face, the sound of their voice, that kind of thing. Nothing sexual initially. And not really any distinctively feminine behaviour. You do also have societal things like females dressed in a certain way and had long hair, but these don't appear significant to me.

Therefore, I would argue that for most people there is a very strong inate preference for physical characteristics that match the opposite sex - which makes sense evolutionarily.

Most people are strictly interested in the opposite sex. I think there is also a repulsion against sexual interest from the same sex (which probably explains a lot of bigotry too). I don't think a lot of people have experienced this, and I'm not sure if its cultural either, but I do posit that if it exists, then its a big men discriminated against homosexuals, or even the reason why it was entered into religious texts which may have just reflected the instinctual feelings of ancient societies without an understanding of the harm this would cause.

So back to my original line of thought. If someone is asking me to treat a trans-female as a female, nothing in my behaviour will actually change nor should it. And the only time it should as I said earlier, as in a physical altercation, the physically inferior rules no longer apply.

So it begs the question of what this societal recognition actually is?

For sexual interest, humans are extremely sensitive to even minor physical attributes, so that most of the time they will be able to tell the birth sex.

But in the cases where they cannot tell the difference...is this actually the ultimate recognition that trans people persue?

I think it's this scenario that may cause a lot of bigotry too, because I think people may feel they are tricked into a homosexual desire, and if they have an innate repulsion to such feelings, then you could understand it triggering an emotional response. But a big question is whether this is "innate" or whether its societal which I will admit it very much may be - in the sense that being gay was traditionally viewed as a weakeness and not fitting desired masculine characteristics that determine hierarchy and power in male friend groups, and also self-esteem.

In terms of genatalia though, I think humans are even more particular, and so even if a trans female was able to look like a female at a distance, and feel like a female on closer examination, a sexual relationship with a hetero male is probably still very rare. But then you have to appreciate that two heteros matching is still not a given.