I’ve vaguely heard murmurings about a secular decline in testosterone levels, but imagined it was overhyped or at worst just a result of the obesity epidemic. @lambdaphagy and I had a chance to just scratch the surface of the literature, though, and it’s frankly alarming.
Total T dropped about 20%, bioavailable T dropped 50%, over 20 years from 1987-2004. The Finns aren’t exempt either. Cohorts were matched for BMI, and even if they weren’t, the effect size of obesity is off by almost an order of magnitude. Doubling BMI causes T to fall by less than half, and, mirabile dictu, American BMI has not doubled (yet, give it time.) Average BMI went from 25 in 1960 to 28 in 2000.
The speed of that T drop is just jaw-dropping. Obesity doesn’t help, but doesn’t explain this level of cratering. So: phytoestrogens, xenoestrogens, micropharmaceuticals in the water, behavioral effects? More work is required, but hit me up if you have any good intel.
Cold Take: Crime declined because we removed lead from the gasoline, lowering the amount of lead-induced brain damage.
Lukewarm Take: Crime declined because we allowed abortion, removing some of the worst-off potential people from being born and raised in substandard conditions.
Hot Take: Crime declined because we put drugs in the water supply and we’re all transgender autistics/neurodivergents now, even the women. (Especially the women.)