When I was a kid I could do at least 10 pull-ups, and now I don’t think I can do one. I’m weaker and fatter. No mystery there. When I was a kid most of the girls couldn’t do pull-ups, just me, the girl who was on swim team hoping to be in the olympics, and a couple of others. The boys were more likely to be able to do one, but I don’t know why girls had much more trouble with it. I would never call myself naturally strong or athletic. The only thing I did as a kid was ballet and PE class at school.