There is a birth crisis. Modern, liberal women are not actually reproducing, they are not keeping their end of the evolutionary bargain (men protecting, sacrificing and dying, while women giving birth). Therefore, there is no need to maintain the old-fashioned, patriarchal system with women as a more protected group. Everyone should contribute equally, pull their own weight. Equal rights, equal lefts (responsibilities).

Western women are already only producing ~1.5 kids (many with none!), you could send 50% of young women to die in war, then have the other half have a fertility rate of 6, like what their great great grandmothers had, and we would be far far ahead already.

50 men and 50 women. You have to send 50 people to the front. You'd send 49 men, leave one behind for reproduction purposes, have 50 women at home and be short of 1 person.

Or we could embrace equality and send 25 men and 25 women, leaving behind 25 of each to do whatever they want.

Can you share examples of this happening in modern history at scale?

That's a thought game, not reality.