Don't these respondents miss some of the obvious advances in reproductive technology? With frozen embryo's/ova/sperm, you could theoretically start with one woman to gestate. Obviously you wouldn't want to put all your reproductive eggs in one basket, so you would need more women (until we have technology to gestate outside a womb). However, I don't think you would need any men initially. The limiting factor would pretty much be womb gestation. Anyway, I don't think more than 10 women would be necessary with enough of the frozen stuff around, cause you could ramp up your population in just a couple of generations probably. Now, from a social dynamic standpoint that is a different matter, and it would probably be helpful to have some men around, but i really don't think you would need too many.