I think it depends on the sport. Men's higher testosterone levels allow them to build more muscle mass and explosive speed--definite advantages in contact sports as well as sprinting, throwing, swimming, rowing, and cycling. Sports dependent more on finesse and strategy would offer more of a level playing field, so to speak. There's also the issue of bodily vulnerabilities, such as knees, where women are prone to more serious MCL and ACL injuries.
What I would like to see is more sports involving mixed teams. We do have that in many community recreational leagues, especially in sports like softball.