I think you guys are seriously overestimating the requirements for military service. FYI, at 16 years old (not even legally old enough to serve as a woman), I could meet the naval fitness requirements without too much trouble, which I proved in the middle of the 6th form common room when me friend questioned whether I could really do 50 sit ups in 2 minutes. When my stepmom was in the RNR she met every fitness criteria at the men's level. Other than special ops and the Royal Marines, which the vast majority of men cannot meet, the requirements for the military aren't all that high. It's just that the denzions of this forum are so fat and lazy that it seems like a huge challenge.
The concern that most people bring up is, as
@AnOminous said, the way women would be treated if captured, but given that Al Quaida (sp?) aren't exactly following the Geneva Convention they aren't actually that much safer in non-combat positions, and aren't going to be treated any better for being medics. Plus, I should really hope the military has more sense that to admit people who don't understand the potential risks of serving, and if somebody wants to get themselves blown up for queen and country then I don't think sex/gender should be a valid reason to stop them.
As for
@Corypheus 's concern about cohesion, that could be used against literally anything else. Hell, it has been! It was the argument about racial integration and the repeal of DADT in the US, and for permitting gay people to serve openly over here. And I will say the same thing about this as I would about those - if somebody is so butthurt about there being a women on the front line that they fuck up, then that is on them, not the woman. Last I checked the only positions currently barred to women in the Royal Navy are submarines, recon, and the Royal Marines, and funnily enough the Navy did not collapse when the Royal Navy and Women's Royal Navy were merged, despite the fact that we do indeed put men and women aboard the same warships. There is minor differences in fitness criteria for men and women - women need 10 less push-up and 10 less sit-up in 2 minutes, and get an extra 2 minutes on the 1.5 mile run - but it isn't as much as you'd think, and you'd be surprised how many women can meet the men's requirement. As I said, it really isn't all that high.
TL;DR: every commonly used argument for not letting women into combat is bullshit, and can be easily proven thus by the fact we've been unofficially letting women into combat since Lord knows when. It's worked out just fine for the Israelis, and while OFFICIALLY, every position in the Royal Navy baring the Marines is non-combat, in practice every position in the Royal Navy is combat, and funnily enough teh wimmins have not yet burnt all of out navel vessels to soot.