No, I would have to agree with 3LilChunks on this one. Children will be children and love to explore everything around them, but as a parent, it's our job to guide our children to what's right and what's wrong. Just because a child wants something and we don't give it to them, doesn't mean it will be damaging to them. Sure, you may have little boys that prefer the color pink, and like to play with girl toys more than boy toys, but dressing them in dresses and high heels is setting them up for confusion later on. I may be the only one here with this perspective, but as a Christian I feel as though gender roles are already defined, and not something that can be chosen. Not saying that little girls can't play in the mud, or little boys can't play house, (some of my favorite childhood memories were made playing outside and getting dirty! :) but it's important to show them certain things pertaining to their gender are not acceptable. I think it's wonderful to foster the character your son is becoming (I've met a couple boys like this and they always seem to be more caring and gentle) :) But I think dressing up like a girl is crossing the line a bit.
If OP was dressing her little boy up in dresses and high heels I would agree with you. But she's not, she's allowing her son to chose his clothes and how he presents himself to the world. She;s allowing her son to explore who he is, all while knowing that his parents love him no matter what. This is an incredibly important lesson for children to learn.
Gender roles are constantly being re-defined. Not so long ago, pink and high heels were considered very masculine.