To my knowledge only country to do that was Isreal in the 60's and it was never fully implimented before it was discarded.
That was over 40 years ago in a different culture, without the technology and tactics we have today.
The nation known as former Soviets do not maintain front line female combat troops either. China, of course, has no need. Only desparate nations, like the former Soviet Union, are pushed to this dire extreme. Well, that and nations under the control of social utopians. The simple facts of the bell curve should demonstrate the expense and futility of pursuing cultural myth as objective reality.