From my search, there are 1% more females in the US than males.... We know what happens when the reverse happens (besides after a war which ex Soviet countries are still recovering from), China is like 3% more males, which is not something we want because we're not gunna send them to other countries like they do.
But immigration quotas is a possible place where I think a gender quota is a good idea, if the numbers don't work at 50:50, then something reasonable. I think especially would be interesting to open source legal immigration. Like rn you kinda need a sponsor, but what if each person had x votes per year for or against individuals and a certain number or votes would add points to your application. And then like if that person is deported for some reason or commits a crime you lose your votes for y number of years. Idk just spot balling.