Thus queried our Vice President.
Well, in point of fact, when you consider that all federal regulation is for the benefit of the regulated (to protect them from the consequences of error), then the current kerfuffle is about the disposition of the sperm. Although it may be a stretch to refer to a one-celled organism as a body, a human sperm does embody maleness. As is often the case, male and female and the law are in a triangular relationship. You know, like the Father, son and Holy Ghost, where the female gets left out. As is true of the Constitution.
Also, requiring males to register for the military draft is sexist legislation and violates the equal protection clause.