Richard Dawkins. The selfish gene (№ 178550)

Incidentally, even those people who are concerned with the problems of population, do not always understand that the growth of its population depends on the age at which people have children, and these children. Because the population usually increases by a certain amount in a generation, it follows that by increasing the gap between the generations can reduce the rate of population growth for the year. Slogans calling "Stop at two" could equally well be replaced by the slogan "Start thirty years!"