"Be fruitful and multiply."

    These words from Genesis are sweet, suggestive, and quite possibly catastrophic.  That spike on the right of the chart above represents 6 billion  people. More than 1 billion of them go hungry every day.  Some  survive by becoming pirates off the East African coast. Others grow poppies in the Afghan countryside or join the Taliban. Still others flee to the jungles of the Philippines to join up with the Moro Liberation Front. The insurrections only reduce the production of food, not babies.

   It doesn't take much prompting from God for people to have children.  On the contrary, it takes a rational assessment of personal and societal constraints, combined with the science of contraception, to limit family size. Having babies is one thing, but you can only put so many kids through college. Especially in a land where childhood mortality is rare but the cost of raising children is high, it makes good sense to limit your reproduction and invest heavily in the few offspring you have.

    But not to fundamentalists in the "Quiverfull" movement. Citing  biblical injunctions, they multiply like rabbits. Nikki Keith, mother of five (so far), "reasons" thus: "Just because America and most of the church thinks that birth control is morally acceptable, it does not make it right in the eyes of God. There are many reasons why we should give God sovereignty over our fertility. God's first command to man was  'Be fruitful and multiply.' Nowhere is this command done away with in the entire Bible. It is ... still valid for married couples today. Children are a blessing from God. Psalms 127:3-5 says, 'How blessed is the man whose quiver is full of them.' "

[See Opus Dei touting the virtues of a family with 12 children here.] 

    Ugh. I'm sure this was true in ancient Judea, when parents had to expect that half or more of their children would die before maturity, and when the nation needed as many children as possible to grow up to be soldiers, farmers, and in a few lucky cases, temple priests. Times have changed.

   Life expectancy in the last century rose by 50 percent in the developed nations, and recently published predictions hold that most children born today can expect to live to 100. The question is, can the Earth sustain them? We have come close to exhausting the seas, we are well on our way to using up the available phosphorus that fertilizes our fields, and we have pretty well exterminated the world's large animal species, outside of a few zoos and preserves. Continue along this path, and we will bump right into famine.

    In evolutionary biology, organisms that have as many offspring as possible are termed r-selected species. They include frogs, salmon, insects, and, of course, rabbits. They are not notable for being good parents. On the other hand, creatures that put in a lot of time and effort to raise their young, such as whales, elephants, and, for the most part, people, are known as K-selected species. But all too many of us seem to be following the r-strategy. 

    Let me hasten to say that I am not, repeat, not implying that people who choose to have many children are bad or uncaring parents. But they are blinded by scriptural nonsense, and they are a menace to civilization. Look at the curve. It cannot continue to rocket upward. It will either level off or crash back to Earth. Which depends on choices we make.

    Christianity and Islam, the world's dominant religions, both push large families (at least, the major denominations do). This quite possibly explains why they are the world's dominant religions. Rational believers must reform or reject those institutions, or consign all of our children to a hellish future. Let's face it:  Those quivers are full of flaming arrows.