I really can't think of any logical reason why women should not be allowed to be in the army (besides sexism, of course). Women are completely capable of being as physically strong as men, and as hard-working, brave, and intelligent. Plus, they are already allowed in the army. There is no reason for things to change.
Having a background both in law enforcement and military, I understand the hesitation in allowing women to operate in certain areas, and sometimes the reasons are many, and somewhat legitimate.
I hold a strong belief that a standard bar should be set, and regardless of if someone is gay, straight, male, or female, they should be allowed to participate.
The only issues are our current levels of testing are poorly designed for this process of indiscriminate behavior. At the end of the day, all I need to know is if I get shot in the chest and need to be dragged into cover, can the person next to me do it. I don't care who they prefer to be intimate with, or how their genitalia formed in the womb. If they can do it than they're my brother or sister. If they can't then they fail the basic qualifications for the military.
Until we encounter more problems with this idea, there should be no restrictions based on arbitrary motivation.
Sexists in this country who oppose women being able to join men in combat always say that women are the weaker sex. But if a woman proves to be fully capable of equally matching a male physically, as many do already, why not let them? Is it because they will be flirting with the male soldiers? No, they are segregated by gender. Will she be all emotional? No, only if you believe in the stereotype of women. In China, North Korea, Israel and countless other nations, women are part of they're militaries to the fullest extent of the possibility. Why not America? Male the country better than it is already?
Women will never be able to match the men physically so she will be a liability to the team. A 60kg woman will never be able to lift a wounded 80kg man to safety. And men will do stupid things to protect the women in their team thus endangering the team and mission.