A Marine Corps report on gender integration indicates that, on the average, women underperform compared to men in the testing done for combat readiness (testing that may or may not be fit to use, but that's a parallel matter).
The problem is that people using those statistics to then say "… therefore women should not be in combat" ignore other data gathered indicating that some individual women outperform some individual men. And if the goal is to get the highest performers, then giving those men the pass just because of their plumbing is counter to that goal.
Averages are useful … but they are only fully applicable if you have to deal with entire populations. If there are women who can qualify, excluding them from combat service because other women can't makes little sense.
There Are Women Who Can Outperform Many Men In The Infantry. Get Over It
A combat arms officer counters the arguments for why women should be kept out of infantry units.