In Korea, anyway. Korea is voting on a new bill that would allow its citizens to possess dual citizenship with other countries after age 22. Current law makes dual-citizen children choose at that age and revokes the citizenship of Koreans who acquire a foreign citizenship and requires foreign nationals who obtain Korean citizenship to renounce their former country within 6 months or two years.
Check out the article from The Korea Times.
So if the bill passes, Min Gi would be allowed to become a U.S. citizen (eventually, if we make it through this whole green card process) without giving up being a Korean citizen AND if we move back to Korea, I could get Korean citizenship without giving up my U.S. status. And our future kids wouldn't have to choose between the two countries. I say this would be a "win" all around.