This could be true. I know for a fact that at least some of our friends here in the US have gone to Korea to have the procedure done, not in the US, due to cos

This could be true. I know for a fact that at least some of our friends here in the US have gone to Korea to have the procedure done, not in the US, due to cost reasons. And obviously our friends still in Korea would have had it done in Korea. That could also explain why I don't notice the prevalence of twins amongst our friends of other nationalities here.