Thomas More conceived of population control as a way to solve problems caused by overpopulation and low birth rates. He believed population control could help maintain a stable and harmonious number of citizens. Some problems caused by overpopulation include increased pollution, depletion of resources, and global warming, while low birth rates can lead to an aging society and decreased economic growth. Both Plato and More theorized that the state should establish rules to control birth rates, though this raises issues of interfering with personal freedom.