I think most parents who have raised both a boy and a girl will tell you that many if not most of the gender differences are hard-wired. LOL.
I am very competitive by nature, but in the past few years, I've beaten most of it out of myself. I can kind of compete with myself, but the need to win things isn't as strong.
I can tell you exactly why I did this, too (and why women probably shouldn't be wired as competitively as men): my children. And the fact that they play competitive sports. Sitting on the sideline, helpless, while your most loved things are out on the court, field, or rink competing is really quite horrible.
I really had to detach my hatred of losing ... I can totally see why awful sideline parents go nuts sometimes. (Not defending it! At all! It's awful!) But when you have a bunch of pent-up competitive energy (because that's how you were made), you have to let it out somehow. For a while, continuing to compete myself really helped, but it wasn't enough. So I just forced myself to start believing all the things about "it doesn't matter if you win or lose" "development, not victory, is the intent" and so on and so forth.
It has not been such a good thing for my tennis game, because now I really don't care so much. And by and large much of competitiveness is not as much a love of winning as it is a hatred of losing. And once you stop hating losing, you'll lose a lot more.
But I'm a lot happier on the sidelines, and I'm a mom, not a coach. The kids already have coaches; they don't need me to do it.