Could it be because I have three daughters that I feel this way?
Yes, yes, and yes.
Agreed. And I'll add the obvious, women serving side by side with men will eventually cause sexual tension. The last thing one needs during war is any kind of distraction that may make you take your eye off the enemy. That will get you killed.
Additionally, if a female is captured by the enemy you have to consider a high possibility of rape. Though that is not to say men aren't raped during war the likelihood is certainly less.