Well said Al R.
I was formerly of the opinion that if a woman could reach the same standard of fitness as a bloke, then crack on. However since working in a unit containing both males and females I have become aware of the dramas and BS caused by the inevitable "inappropriate relations" between various members of that unit.
While the effects of this may be an acceptable with other units, I can't see the benefits that females in infantry units may bring outweighing the damage to morale and unit cohesion that would be caused in an infantry unit.
Just my 2 cents.