Why can't we grow beards?

It doesn't matter. To sacrifice a beard to be part of something others are unwilling, too afraid, or incapable of doing seems a small price to pay.

Your thoughts dont mean dick. You're supposed to shave every day so do it or get out. Join the Salvation Army. Or the girl scouts.

Oh really??? Hell Cpl. even our civilian Work Place Saftey Group AKA OSHA is death on using a respirator with a beard IE if you wear a beard that inhibits a good seal your dead!!! The answer is that "other nations" do NOT fear the use of Chemical, Biological or Radiological weapons even thou that yes two out of the big three have been used!!! Iraq, Syria... Remember Uncle Sam will have to pay if you do not wear a mask correctly, directly to your parents. Because you will not survive.
Hell, Cpl just for fun how about you do the dying roach dance on the floor...

Just to be a bit of a smart ass... Have you seen the raggedy, scraggly beards most males have until they hit their mid 20's or later? About half the first term enlistees and Lieutenants would need face wigs.

Regs....thats why....

Beards cause many problems in the health department. Clean appearance, taking care of a beard takes more time than keeping a shaved face, I know I now have a beard and it takes more to keep it looking nice.

Making the statement that "other nations allow it" does nothing for your argument. In fact it reeks of "Johnny jumps off the bridge, I must do so as well"!
Grooming standards are grooming standards. You signed the paper, you volunteered, you follow the standards. That's it.
I served when facial hair was allowed in the sea going services, then it wasn't. Guess what? I shaved. I didn't really like it, but the alternative was not acceptable to me.
Bottom line, you cannot have a beard because it isn't allowed.

I don't see a reason not too as long as it's kept in a neat appearance and doesn't hinder the NBC mask.

The reason the Army doesn't allow beards is that they prevent the protective mask from properly sealing. Think that's bogus? The reason Hitler wore that little clipped mustache was because in WW I he wore a handle-bar mustache like many others on both sides. When his unit was attacked with a chemical agent he tried to don his protective mask. Because of his mustache the mask couldn't be properly sealed, as a result he spent months in hospital while doctors tried to save his lungs. He clipped his mustache so he would never have the problem again; he kept it clipped as a reminder of what he had gone through.

I thought the military was very picky these days. Dont know about the Army, but in the navy,on board ship. You better be clean shaven enough to make a great air tight seal for your fire fighting SCBA,or your going to be breathing in alot of toxic smoke. And i hope your NBC mask is nice and air tight also. Id hate to hear about any of my fellow brothers and sisters getting a lungs worth of mustard gas.