" The rise in voluntary childlessness, like the decrease in fertility and the increase in homosexuality, may be an evolutionary adaptation to overpopulation. Or, since the phenomenon is more prevalent in the West, maybe it’s an effect of wealth and plenty. (Having more offspring is to an individual’s evolutionary advantage in impoverished conditions, even though it’s disastrous for the species as a whole and has made places like Rio and Calcutta some of the least desirable real estate in the solar system.) "

― Tim Kreider , Selfish, Shallow, and Self-Absorbed: Sixteen Writers on The Decision Not To Have Kids