Wednesday, September 3, 2008

Sex and Money

These are difficult economic times. People know that their bank balances, gas costs, and vanilla frappuccino budgets are affected, but now a researcher at UC Berkeley points out that sex lives are, too. In bad times, libido is lowered, and people have less frequent sex. That didn't surprise me, but another side effect of economic hardship did startle me: During depressions, fewer boys are born than girls.

Economist Ralph Catalano looked at birth records for East Germany from 1946 to 1999. Just after World War II, and again after the 1991 collapse of the East German economy, fewer male children than normal were born. The difference was statistically significant. The reasoning is this: It's well known that male fetuses are at greater risk for miscarriage or premature birth than female fetuses. Economic hardship creates stress, and pregnant women under stress may be more prone to miscarriage and premature birth. So fewer male children survive, creating the imbalance. The same thing happens after an earthquake.

What interests me is the evolutionary implications. When conditions get tough, nature produces more girls, which will be needed to (eventually) raise the population level that may have decreased from earthquake or famine.

I just found out yesterday that my school taxes (New York State has the highest property/school taxes in the nation) went up another $1500 as a result of reassessment plus a tax increase. If I were in the child-bearing stage, I'd be having female triplets.


Nick A said...

In silicon valley, there's ongoing 'informal chatter' that the area is now a long-term engineering breeding experiment. Driving that line of thought is both anecdotal and quantitative data showing a significant increase of kids who fall into the autistic spectrum. The root causes are probably very difficult to confirm, but your blog entry made me wonder if a perpetual 'high stress / startup' work environment could be trended.

Ann said...

Interesting. I wonder what effect deliberate gender preference has on mother nature? Like in Asian countries where boys are starting to badly outnumber girls. What will be the long term effect of that messing with the natural order?

Nancy Kress said...

Well, our excess of girls could eventually pair up with their excess of boys. Send away for an American bride?

bluesman miike Lindner said...

So you hear that, wonderful females?

Better take care of your guys better!

'Cause we might not be around too much longer!


Kosmo said...

Nick, I'd heard about that autism spike in silicon valley. Very interesting stuff.

Some of the genes which increase one’s risk for autism also, apparently, increase one’s risk of moving across the country to end up a silicon valley engineer. (where one is then likely to meet an engineer of the opposite gender, fall in love, and make babies-- some of which will have an unhealthy double-dose of said genes.)

Mark said...

There's another factor to consider: There was a time when the problems we diagnose now were put down to another cause or called something different. Eg: There wasn't always a "hate crime", it was called what it was, assault and battery. The same is true of physical illnesses.

TheOFloinn said...

Paul Colinvaux once wrote that war is the price societies pay because they cannot afford daughters.

Population increase depends solely on the number of women in the child-bearing cohorts. Men are largely irrelevant, mathematically, and when I was doing grant research in grad school, we only needed to "assume a sufficient number of men." In a village of 100 women, there can be at most about 100 births (not counting multiple births) in a year, regardless whether there are 100 men, 1,000 men, or 1 very tired and happy one.

But what happens when m >> f? One of the societal functions of marriage has been to domesticate young men. If we look to places where marriage has collapses, we often see the return of the primate "bachelor herd": restless, mateless, horny young men roaming about and making trouble for the clan.

In some societies, the powers that be (PthB) made active use of this. Chaka Zulu famously forbade marriage among the young men, housed them in age-cohort barracks, and trained them in war to great effect in the mfecene. When they were sufficiently blooded, he married them up in a mass ceremony and they were placed in the "reserves."

The elders of Sparta did something of the same sort.

Remains to be seen how China handles it.