Super hard to say. But there are a fiew things you should definitely do: - Make sure not gender is valued above the other gender. - No 1 child limit (instead

Super hard to say. But there are a fiew things you should definitely do: - Make sure not gender is valued above the other gender. - No 1 child limit (instead of 2), with a 1 child limit we would have two people having one child, i.e. halving. Which is probably faster shrinking then any country can properly handle (i.e. after a while a horrible ratio of young to old people etc.). A two child limit still will cause shrinkage. - Don't fixate the law on women, it's unreasonable and put's a further burden on them. - Make sure your social system isn't incompatible with such a law before enacting it. - Make sure society is compatible with such a law before enacting it. - Make sure it's not turned into a money making machine. - Consider regional differences. Which would be a view points you should keep to which china didn't bother with at all. Most problems of the past one child policy in china come from: - Man being valued much more then woman now leading to there being much more of them then woman. - To fast shrinkage puts the social system in danger as to view young people have to care for to many old people. - The laws being abusive to woman. - The laws unreasonable handling of children which under the law should not have been born but have been born anyway. EDIT: Just to be clear, there are many more ways to (slowly) shrink a countries population which are based on subtle nudging society in the intended direction instead of enforcing any hard limit on the number of children. Which is probably what China should have done, tbh.