The family is the foundational unit of their society. A family group ordinarily consists of three generations with between 10 and 16 persons, not counting their children. The senior male member is head of the family.
The population of each city is maintained at about 6,000, and in the event of a marked rise in the birthrate, some families are sent to other cities where they can be accommodated. If the population of the entire country exceeds their prescribed norms, some are sent as colonists to other countries that are not so densely populated.
One of the features that sets More's Utopia apart from numerous other works in the utopian tradition is the importance placed on the family. It is the primary unit in the structure of society. It furnishes the center for human companionship, instruction, discipline, and loyalty. That role for the family has been so deeply rooted in the culture of our civilization that it would scarcely be remarkable were it not for the fact that it is not universally adopted by utopianist writers, Plato being the first notable exception.
It is well known that More himself was a devoted "family man."
The idea of population control seems like a modern concept, but it must be noted that by that term More does not mean birth control.