I have friends with little girls. Girls can be manipulative. They get cliquey and mean to each other. I know from what a brat I was. And it's distressing that so early on they get into clothes and looks and weight.
Boys wear their hearts on their sleeves.
You say you were a brat. I can remember incidents where I was so mean to people. I think back to them specifically, and I think how awful girls can be to each other. Well, I assumed that I'd have some because that's what you do in life, but I never had a burning desire for them. Now, perhaps had I found that I couldn't get pregnant, then the desire would have really grown.