In the United States, the Virginia-based company MicroSort has been helping parents give nature a nudge since 1996, through a process called cytometry that separates X and Y chromosome-bearing sperm cells. Seventy-nine percent of the company's clients shoot for girls.
Sounds like a good basis for trade.
Trade in what? Psuedo-lesbian porn?
Not a surprising development if you look at it from a the-US-is-becoming-more-fundamentalist socio-religious point of view. Multiple wives per husband is quite a common feature of what might be considered more fundamentalist cultures. I'd say these people aren't likely planning as much for extra-national trade, but rather are anticipating increased domestic demand.
Ever read _The Rainbow Credenza_? Sex imbalance ends up being a big driver for social change in that book....
I've read several places that there are many villages in India where the male/female ratio is out of whack enough to cause some big problems, as a result of portable ultrasound machines and cheap aboritions. It will be interesting to see what comes of that. I know there are cases of immigrant groups with a large sex imbalance (including the Chinese in the US at one point); maybe looking into what happened in those cases would yield some insights....
--John