In the majority of the world, and through the majority of history, the main cause of death to women is childbirth. And although they can eliminate this risk by eliminating the behaviors that lead to pregnancy, they choose not to. This is ultimate risk taking behavior. So please, don't relegate risky behavior to genetics. I think if you widen your definition of risk, you will soon find that women partake in many, many risky behaviors everyday--ones that they could easily pay for with their lives. Climbing just happens to be marketed mostly to men; but that is changing. I think over the next ten years, the ratio will continue to shrink rapidly; much more quickly than "evolution" would explain.