Down with the heteronormative hegemony!

My new word for this week is heteronormativity. The word is cobbled together as well as the concept it stands for: that there are but two ways to be a normally functioning human, and it all depends on one's genitalia. If you have a penis, you must be masculine and be sexually attracted to the vagina-endowed humans. If you have a vagina, you must be feminine, and be sexually attracted to the penis-endowed humans. Your biological attributes (sex) determine your cultural role (gender) and whom you want to fuck (sexuality).

How can this dichotomy possibly go wrong?

(As an aside, I wish there was a 'sarcasm' font.)

There are two main questions here, as I see it. First, why should one's biological attributes be connected to one's cultural role, or to whom (if anyone) one wants to screw? Second: why should 'normal' be in any way connected with 'worthy'?

In both questions, the problematic word for me is 'should'. That word to me phrases the discourse in a political, or perhaps even religious framework, which allow for dictations of morality. It doesn't sit well with me, because my immediate reaction is: who's to dictate? That's right, I'm queer through and through. The burden of proof rests upon those who would dictate, and as a mathematician, I have very high standards of proof.

Instead, I rephrase the questions into something explorable without dictation, and the questions go forth and multiply:

1. Is heteronormativity rewarded? For what reasons?
   
2. Is non-heteronormativity punished? For what reasons?
3. Are there any social benefits for this procrustian bed? Detriments?
   
4. Is biological sex dichotomous and unambigously defined?
5. Do socially perscribed gender roles have any natural connection with biological sex? Which roles, which functions, for what reasons, and do they truly exculde people of another sex of performing this role, or merely tend to do so?
6. Is sexuality well-defined? Is it unchanging? Are there natural connections between one's biological sex and whom one wants to fuck? For what reasons? How strong are these connections?
7. Can one's sexual desire be influenced by nurture? How, and to what extent?

Dot, dot, dot.
From my admittedly limited knowledge, beginner answers would be:

1. Yes, for historical and religious reasons.
2. Yes, don't know why.
   
3. No idea.
4. Nope. There are definitely people don't clearly fall into the two categories, which change anyway. It used to be that the genitelia were the primary criterion; now it's the chromosomes, and those don't fall into two categories either, and don't necessarily correspond to the genitelia.
   
5. Some tentative connection based on evolutionary arguments, but only some have a strong connection. For example, only vagina-endowed humans can give birth (except for the special case of a female-to-male sex change), but not all vagina-endowed humans can do so.
6. No, no, some connection based on evolutionary arguments but the connection isn't very strong. For example: more than half of the women have no nerve connections within the vaginal canal, and thus don't climax from intercourse. Not much insentive for getting it on with the fellas.
7. Sure, and rather greatly, if the ancient Athenian society is any indication.