Got any evidence on that?

I do. While I'm not a GL, I have some anecdotal evidence you might be interested in hearing. I personally know a sweet girl, 6, who sometimes talks to me about male celebrities she finds attractive. When we were swinging on the playground one day, she exclaimed that a man across the yard was "sexy." She and her other friend hopped off of the swings, walked across the yard together, and explained that they were trying to get the guy to notice them when I giggled and asked what they were up to.

On one occasion she told me that when she turns 18, she's going to have sex with everybody. Now does she literally mean everybody? Of course not, but nevertheless she is interested. And she has very coddling parents who get uncomfortable when she or her sister mention anything even remotely sexual, so it's unlikely that she's been "taught" this behavior by anyone.

As someone who was once a little girl, I can tell you that the feelings are already there long before the words are.