Importing human mass from mars is not really self sufficient. 1. The website estimates $500/kg for Earth to Mars, but that number has to go significantly up fo

Importing human mass from mars is not really self sufficient. 1. The website estimates $500/kg for Earth to Mars, but that number has to go significantly up for human cargo. It could easily be $250k to ship a human if cargo weight is $500/kg. The math works out that replacing the population would cost $250M per rotation. It's probably easier to have kids, even if 4% of the population is dedicated to the task. 2. Finding colonist that will be psychologically prepared to not have kids will be significantly harder than not filtering on that variable. This is the type of thing that can weigh heavy on the mental health of colonist.