I think the Israelis tried women in frontline combat units and it didn't work. Same with the Russians IIRC. Quoting: s. d. butler
There are certainn complications with women in combat positions. here are a few:
1. Generally, women are only about 60% as strong as men, so they suffer a serious disadvantage on the battlefield when having to perform physical tasks and fighting against men on the other side. If your battle buddy takes a dirt nap, you must be prepared to carry him (or her) out of harms way to a medic. If your battle buddy is a small girl, she might not be able to carry you out of harm's way to a medic. That is a problem.
2. Women and men like to form emotional attachments to one-another that are often a distraction on the battlefield. If your girlfriend beside you gets her head blown off in a firefight, you might become a little too distracted to continue the fight. Plus men will be fighting each other for the affections of a pretty girl in the unit. It can lead to unnecessary emotional tension and moral problems within the organization. Everyone will hate the boyfriend of the pretty girl on the squad if he too is on the squad, as he'll be the only one getting laid while everyone else will have to suffer with hearing all the action. This will cause resentment, jealosy and sometimes violence within the unit. Everyone will want a piece of the action.
3. Mixed sexes together on guard duty at night (gays too) will sometimes be paying more attention to each other than to their security, which will compromise their mission.
4. That will sometimes lead to pregnancies, which will weaken the fighting force unit cohesion when they have to take off for maturnity leave.
5. Life on the front lines is often very austere, without luxuries such as bathrooms and showers, so there will often be a severe lack of privacy for the women. She might have to take a dump out in the open in front of all the men, lol. And shower or sponge bathe outside with them too.
6. In urban and jungle environments, often combat is done in very close proximity with the enemy. In such situations, your sense of smell can be an asset. And odors can be a liability. If you can smell cigarette smoke, you know someone is near was was near not long ago. The same goes with perfume, deoderant, cooked food, and body odor/menstration, chewing tobacco, etc. Personal hygeine often seriously lacks on the battlefield, with a lack of water to wash with, and time and other resources to shower. Everyone is dirty, grungy and generally in a nasty condition, so that could be a problem.
These are just a few examples of the complications of adding women to the battlefield. I'm sure there are others.