Balls. Testosterone to be specific.
Given all things other than gender are equal (nutrition, training, resources, etc.), a man will be significantly stronger and faster than a woman in any physical contest.
Testosterone is the key hormone needed to build muscle mass and a natural woman will not have access to the amounts of testosterone produced by the testicles of a man who has reached puberty.
I know you're playing devil's advocate, but this is grade 5 health class stuff. You should already be aware of these basic physiological differences between genders.