That's the only reason that suffices to explain why women can't pass Marine fitness tests:
With the news coming out today that the sole remaining female Marine has dropped out of the Infantry Officer’s Course (CNN, Marine Corps Times*) it seems like a good time to look into why women in the military are having so much trouble meeting physical fitness requirements.  According to the CNN video below from January of 2014, the reason women lack upper body strength is women aren’t taught how to do pull ups.  Here is the relevant exchange between CNN Anchor Don Lemon and CNN Pentagon correspondent Chris Lawrence:

 Chris Lawrence:  What they’re gonna do now, is… looking at better ways to train women to do these push-ups [sic].  There is a feeling that from the time they are girls, girls don’t do push-ups, even women who workout religiously and are very physically fit are not working those kind of muscles and trying to build up that bigger upper body by doing pull-ups.  So, what they want to do is go in and really teach women better ways to train to do this particular exercise.

 Don Lemon:  Yeah, working the upper body that’s a guy thing, right?  And I mean, guys you see at the gym with skinny legs, big upper bodies.

 Chris Lawrence:  It’s the beach muscles.  It’s the beach workout.
What I find interesting about this is the way it shows how every female failure inevitably turns into a discussion of male shortcomings.

Because no woman can ever fail at anything for any cause other than male perfidy! To admit otherwise would be to jeopardize the Narrative.