Must be a weird mindset to reduce everyone you meet to their disembodied genitals, Schadenfreude. I'm afraid I don't quite follow your train of thought with the whole HiV analogy (accepting trans people is equivalent to The Scramble for Africa?), although at a guess that train has long since derailed.
@shua, I was talking about nude showers, which is a different kettle of fish. If people are wearing consumes then I see no reason to worry, or even bother segregating the genders at all (providing of course there are appropriate private stalls for the shy)
young boys will like to try to peek in the stalls when given the opportunity to see the mysterious other. no, it is best to have separate rooms altogether.
societies have cared about gender in ways that are not completely identical to sex for ages. and they found ways to carve out spaces for this to fit this around the dominant gender roles that were related to sex. What's new here I think comes out of both a politicization of gender under the idea of rights and a real contestation over the relationship between biology and identity (both of which claiming ultimate importance), so that transgenderism shakes ideas about gender to the very root in a way that it hasn't before.