Then why should men be drafted?  Would mommy's son who has no desire be a benefit or a determent?  The issue of pregnancy went to court and it was ruled that pregnancy is a choice and the military can not control it, same as any other profession.  Not only that but male members of the military are also entitled to family leave, not as long since they do not go through pregnancy/childbirth but they are still critical to the child's welfare.  The military has to compete to get better quality recruits otherwise who would join.