The idea that gender is a social construct, proposed in the late '70s by Don Zimmerman and Candace West took some time before being given consideration in the academic world. Roughly, their argument was that what defines being a man or a woman is the product of social practices and values of the time.
While we may have some trouble accepting the idea ("But you are being born a wo/man!"), the LGBT community has long challenged - even if only from the margins - our ideas of male/female essences. Gender does not necessarily follow from your biological sex. And even biological sex is more complex than the simple pair male/ female would entice us to believe.
Browsing the Thinking Blog, I came across the story of Bulent Ersoy, a singer from Turkey - and while information about her is scarce in English, here's a song of hers:
If you're wondering how she's challenging our constructions of gender, then, like me, you didn't know that Bulent Ersoy was biologically a man, undergoing a sex change to become a (biological) woman - after all, we still find it hard to accept that you can be a woman without the appropriate biology... Along with other celebs like Dana International in the late '90s, such public icons challenged our own definitions - and in certain instances, acceptance - of gender diversity.
That we have an uneasiness in acknowledging the social nature of our gender identities should be quite obvious from the fact that the what really captures our attention is not the music, or the talent, but the question: "Was she a man indeed?"