I think there is a big difference in buying him a new dress in a shop, as a "serious" present, or buying him one from a charity shop, or giving him an old one.
I think boys and girls should dress and dress up however they like, but to buy him a new fancy dress, I mean, if you'd go out for a meal or to Gran's, would you then dress him in his best dress?
I think that is possibly not even what the lad asked for.
My DS fell in love with an old silky nighty of mine, I gave it to him when he was 2. He still sleeps with it next to his pillow (he is 11 now
).
I gave my other son a doll's house when he was three (not a pink barbie one, mind).
Both my boys have ended up quite gender stereotypical after all, so it was nice to indulge them in their wishes for girly stuff when they wanted that.
I am all for letting any kid wear dresses, as long as you also allow him to wear rugby tops, wave light sabers or play football, if that is what he suddenly likes when he is 4.
I am slightly suspicious of parents are making a point about anti-genderisation (is that even a word) by making a big show of how "girly" their boy is, and I don't like it when parents use their kids to make a political point.
I think it is important to let kids just be, in a dress or naked (that was my youngest DS! naked until he was about 4, he grew out of that too) or as a football playing cowboy 