I think the POW should support sensible population control and methods that can help to aid this very important need.
He can not demand but only suggest and its obvious he can not promote one method only nor that there should be a dictatorial amount of children that can be allowed to be born within a human relationship. Maybe incentives against having too many children and most defiantly promoting free birth control. In the end its all about leaving the world citizens with the responsibility and informing the worlds citizen why there is a need. Plus advising world government on taking the latter approach.