What OP has done, actually, is to offer a (partially) testable hypothesis -- that women's athletic performance potential correlates with their reproductive potential. Some of her examples were poorly chosen. Some posters have also suggested reasons why the hypothesis would be hard to test: changing historical and social conditions, shallow historical data for women athletes -- to which I would add the tremendously different kinds of specialization found in different sports. Nevertheless, there is room here for a whole series of interesting studies. We're all aware of exceptional cases, but I have no idea of what systematic studies would find about the cross-career differences in men and women in sprinting, distance running, swimming, tennis, and the three disciplines of fencing.