Hard to say but I can give some insight as to what the kid may thinking as I basically grew up the same way. Since being born till I was 6 years old the male to female ratio in my family was 3:4, my gramps would end up being my father figure and I had my cousin but he's only 2 months older then I am. From 6 all the way to my now 20's I grew up with all females as I moved to Canada in 91. So from there the ratio changed to 1:4 that being I'm the only guy with my aunt, other cousin, and my mom.

At that age I honestly think the "choice" of costume that kid picked doesn't really matter as that age is still young to consider your sexual preference. If the kid grew up with scooby then he just likes Daphne. Although I wouldn't approve of the choice of costume I'd still have to let the kid pick.

The only time I would have to start to worry is if his choice of costume tended to be similar every year that being a female character. But if its just happened for 1 year I say let the kid have fun. After all your only young once anyway.

I have a few problems just with the way she tells the story-almost like she's giving the opinions of 5 year olds the same sort of credence she would an adult. I know they're kids so things don't matter as much to them, but that's the point of having a village around to raise the child-or even consulting and trusting in your peers opinions more than your inferiors (children as a rule should be inferior to their parent, else there's some potential problems.) So overall I'd disagree with letting a 5 year old male surrounded by female's dress as a girl-not because I think it will turn him gay or something like that, but rather that it will simply create issues within himself he might otherwise not have. I'm thinking of Nietzsche here, the dude went nuts from three sisters and an overbearing mother.

In general though on this one I agree with Endyss that maybe she's making a pretty damn well documented case of all this for some reason, and in general I think kids really need to stay out of politics. What happened to the days of Chelsea Clinton during Clinton's presidency? Keep the kids at home until they're legal to vote. We keep their votes from them because we feel they're not capable of making valid decisions, so don't have them out their holding your pro/anti gun sign or pro/anti abortion signs and so on.