Thursday, November 30, 2006

Western birthrates headed for an upswing?

Randall Parker isn't concerned about fertility rates below replenishment in all of the developed world save the US (which is right on the cusp) and Israel:

We are going to witness an increase in fertility as both genes and beliefs that favor fertility get selected for. It is not reasonable to expect the human race will escape selective pressures for higher fertility.
My problem with that is fecundity should have been progressively selected for throughout human history. Even without widespread contraceptive availability that has characterized most of the developed world since the seventies, a method known as coitus interruptus has been used for thousands of years with a failure rate in the upper teens, and this is from a lack of self-control--done properly, the failure rate is basically nil. Comparatively, the failure rate for the pill is about 10%, and for condoms it's around 15%. Historically, those who've not wanted children have had ways to avoid having them to an extent that alleles favoring lots of procreation should have risen to the fore.

Randall points to a slight edging up in the total number of births in the US from 2004 to 2005 (from 4,115,052 to 4,140,419, an increase of 28,367--see page 4). But Hispanic births jumped 36,513. In other words, non-Hispanic total births decreased from the prior year. All of this drop occured among whites, who lost 12,178 births as a group, a decrease of .5% from the year before.

I worry that culture may be more important than genes in this case. Spain, for example, had one of the highest total fertility rates in Europe only a few decades ago (nearly 3 children per woman). Franco's Spain was characterized by pro-natalist policies including the banning of contracpetives and the encouragement of large families. Thirty years later, with the Socialist Worker's party in charge, Spain has plummeted to the bottom of the birthing barrel, even by European standards (with a total fertility rate of 1.28).

Even if the desire to birth children (rather than just to have sex) is influenced primarily by genetics, Occidental fecundity will take several generations to turn around. But the effects of increased birthing on the size of the total population suffers from lag a few generations in duration.

Consider a hypothetical community in which 50 men and 50 women drop out of the sky as infants (total 100). Each live to 95 and give birth to one child (the women does) at age 30. Thus, after 30 years we have 150 people. Of those 50 newborns, 25 are men and 25 are women who will follow the same pattern. Thirty years later, we have 175 people total: 100 at age sixty, 50 at thirty, and 25 infants (population still growing).

Another 30 years, with the same birth cycles for our third generation (say 13 are women, 12 are men) and we now have 188 people total. But the age distribution is economically disastrous: 100 people are ninety, 50 are sixty, 25 are thirty, and 13 are infants. Supporting the people on top is smothering the younger generations, especially the 25 who are currnetly thirty years old.

The economic burden of supporting the senescent people makes it likely that they will have even fewer children than they did (relative to their parents). It's a vicious circle. This is where the West is today. Thirty years later the proportions are the same, but the population has finally started shrinking (because the largest first generation finally kicked the bucket): 50 people at ninety, 25 at sixty, 13 at thirty, and six infants (94 total people).

Now we are in free-fall. Thirty years later at the same births per woman, and we have only 47 people (25 at ninety, 13 at sixty, 6 at thirty, and 3 infants). If we do finally get our act (er, bodies) together, it takes generations for the momentum to actually shift. Let's say instead of plummeting, that last generation actually became thrice as fertile and had three kids per woman: 25 at ninety, 13 at sixty, 6 at thirty, and 9 infants (total 53). The next generation similarly has three children per woman: 13 at ninety, 6 at sixty, 9 at thirty, and 13 infants (total 41). Three generations into three-children women: 6 at ninety, 9 at sixty, 13 at thirty, and 20 infants (total 48). Four generations of birthing well above the replenishment rate, and we still have fewer people than we did at the height of the single-child generation.

Thankfully, the momentous global demographic changes are beginning to be brought up in the mainstream media. As people become cognizant of the fact that in 1960, people of Western European ancestry comprised 25% of the world's population. At the century mark, they made up 17%. By 2050, they'll make up only 10%.

Unfortunately, the quickest political fix will be to import people with higher fertility rates, increasing the total population and upping the population growth rate at the same time. France has one of the highest birthrates in Europe. It also has the largest Muslim population on the Old Continent. The southwestern states have some of the highest birth rates in the US. The northeast is below replenishment. This is a strategy to replace people, not replenish them.

I'm not mollified. The numbers game continues to worry me and others.

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