Men are not the same as women. There are immense differences and if you ignore that basic reality you do so at your own peril.
Imagine for a second, a woman plays on a team in the NBA. Do you think the team really wants that kind of circus? How can you not understand that something like that will take a lot of focus off of the game, the strategy, the locker room, the media, the attention, team chemistry. Oh but it's a good idea because it will sell a lot of jerseys/voters.

Plus, I know plenty of ladies who have went into the military only to get knocked up in the first 2 months and come back home.
In order to ensure that a military memberās pregnancy does not have a negative impact on military operations, the Department of Defense (DoD) and the individual military services should ensure that they have robust training programs in place to educate both men and women on their responsibilities as potential parents, the options to prevent unplanned pregnancies, and their obligations to meet their service commitments. Additionally, each Service must prepare assignment policies that will allow quick filling of billets, including for reasons of pregnancy.
http://www.4militarywomen.org/Pregnancy.htm