Gender, a social construction
Biological sex is something ; gender, the social construction from this biological sex, is an other thing. Strict, socially controlled identities, are over. We know from Michel Foucault and other historians some stories of famous transvestites, having to choose between two strict identities : male or female.
What we now call "queer"  is not modernity being always more crazy, it’s rejecting totally the idea of gender. Long haired boys, girls in trousers in the 60’s and 70’s, and then drag queens, butch dikes or trans (transvestites or transsexuals who go further in their bodies), are the most shocking symptoms of a society that no longer wants to submit its appearance and behaviour to predefinite norms.
About the skirt
Pierre Bourdieu showed in Masculine Domination how the skirt litteraly built the female body : little steps, legs sticked one to the other, and impossible to sit anyhow. The skirt also shows legs, which have to be perfect : beautiful, not a hair. To a feminine body naturally less-haired we demand socially not to have a single hair. Skirt helps to control this norm.
You wear a skirt even when it’s cold, on the contrary of the male trousers that you wear even when it’s warm. The suit, male or female, ignores seasons. You don’t wear it to be warm, but to show you are part of a society, of a social class, and even more to one of the two socially definite genders.
This social construction of gender is associated to a task parting : domestic, professional, and sexual. The feminist fights told us how this parting was an inequality, in terms of time, money, freedom, social status.
Let’s examine the construction of norms in sexuality : the heterosexual act is set around penetration, mostly vaginal : caresses, oral sex (to the woman and then to the man !) are just the forecoming or the penetration, being achieved with a male (possibly also female) orgasm. Feminists fought for the freedom to have this penetration like they wanted, thanks to contraception and abortion.
But this penetration, with an active and a passive, a dominant and a dominated, is too well in the social order for us to accept it. Other sexual practices (oral sex, couple or single masturbation, S&M) can give us pleasure. Why then should penetration be compulsory in gay and straight sex ? And if penetration becomes a sexual act among others (place it deserves), why couldn’t we stop saying "fuck" and "get fucked", "penetrate" and "be penetrated" ? Could we say "englobe one’s penis with your anus" or "prison a dildo in your vagina", to get rid of stupid active and passive grammatical forms...
All of us got it into the ass
In her books Beatriz Preciado reminds us we are all equal considering our anus. Biological men and women, gay, straight or bisexual, we all have an erogenic anus. You can prefer being licked or touched or penetrated, but shit, this is a great pleasure zone for all of us who tried.
But anal sex is associated to domination relation. In the ancient Greece, mature men used to penetrate adolescents when the contrary was stictly forbidden as a perversion. And in our days good men don’t dare to ask it to good women, but wants if from a slat or from a girl "who likes sex" (sometimes to makes the difference between women you respect and women you fuck, them bitches). And no way to penetrate the straigh man anus !
In this layout, penetration is a political act. Penetrate without accepting to be penetrated, it is accepting up to your bed an hetero-centered patriarcal order. To be really subversive and liberated, mister, useless to consume lots of sex in a trendy way with many partners : a nice dildo in your ass would do you more good.
 gay and lesbian movement against middle-class homosexual norms : being queer is being a poor fag or a stupid dike