I speak only for a subset of male geeks, as I know nothing at all of the working of the minds of the other sex. And few enough of even the male geeks as, growing up I was the only person I knew whose favorite author was Bob Heinlein. I suppose that means I can only speak for myself.
When I was nine, I received a box set of Heinlein's juveniles. The same set my Dad owned for years. He only outwardly gave them up, in the years following when he stumbled across one of my books he claimed it back onto his shelves. For a preadolescent geek-in-training, these books are wonderful. Most of them revolve around an individual or group of youngish smart kids, and how they grow up while learning a bit about people, life, and other creamy good stuff. Coming of age stories.
For me, those books were a godsend. I rarely felt accepted in school. When I did, it felt like the people I associated with weren't accepted as a group. As with many other books of the genre, these juveniles portrayed a guy, sort of like me, who could be popular, successful, and athletic. Important things sometimes growing up, neh? In my own life, they were. I've always had this perverse desire to be accepted, to be a part of a community. Other goals and ideas have become as important but that desire, the desire to belong, has never diminished in strength.
I am not finished growing up yet, but I am further along the path. Heinlein and his work made what had been a painful time bearable.
And then there were his soft porn bestsellers. Gives a young teen (think thirteen, fourteen) all kinds of odd ideas about how things should be.