> the cause (or causes) must lie with changes in our environment or lifestyle over the past few years. This is not exactly true. The time span here crosses fou

> the cause (or causes) must lie with changes in our environment or lifestyle over the past few years. This is not exactly true. The time span here crosses four or five generations. That's enough time for genetic forces to be at work. People keep forgetting that very large numbers of children died of infections before the 1950s and 60s. Very large numbers of people walking around today have genotypes that for most prior human history would have been eliminated. You also increasingly have a lot of people walking around who wouldn't exist without fertility therapies. I suspect this plays into a lot of disease trends but it's really never mentioned in the press.