Last year there was a story about a dad in Germany who started wearing a dress in public — just so he could make his 5-year-old son more comfortable. The kid liked to wear dresses himself and they lived in a conservative town that made a big issue of it. (Gawker called the dad "Father of the Year" for being so supportive.)
My kids don't do any gender-bending with their wardrobes, but Elliot has started wearing a tie in situations where it's not appropriate. (It doesn't help that he frequently pairs it with a t-shirt.)
Alice, meanwhile, will wear a tutu in a non-ballet environment.
Unlike the German kid, my children are only slightly eccentric with their fashion choices. Commensurate with that, I'm only slightly supportive.
This is probably why I'm not Father of the Year.