I used to worry that dysgenesis was leading us towards a world in which everyone was really dumb. That fear has been at least partially alleviated by new research showing that more educated people are having more kids. But now I worry that dysgenesis is leading us towards a world in which everyone is really sick.

Historically, human reproduction used the following strategy: have 6 or 8 kids, and the healthiest 3 or 4 would make it to adulthood. Now couples have 2 or 3 kids, and they almost all make it to adulthood. But that implies that lots of marginally-healthy children are surviving, thanks to medical technology, and so the gene pool is getting less healthy.

Look around you and count the number of people who have some kind of debilitating allergy, chronic illness, or mental health condition. Does it seem scary to you? What if that percentage goes up dramatically in the future, while the conditions themselves also get worse?