4 Comments

Fascinating and the sample sizes are convincing - clearly something here.

I wonder whether there may be some definitional differences with older parents? That is, do older fathers (and mothers) tend to be wealthier and thus to prefer some of the more plastic diagnoses? ASD is a case in point; it may be more socially desirable to have a high-functioning autistic, than a cognitively disabled child.

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I wonder if this could be investigated using historical data, like the one used by Gregory Clark in social mobility research. It could be investigated if having an old father leads to depressed social status and fertility of the family in subsequent generations.

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I've read some studies on IVF on the effects of freezing sperm and eggs. IVF can be done with "fresh" eggs and sperms. But they achieve a higher success rate by freezing the sperm and eggs and then thawing them and then fertilizing them. Only the strongest and healthiest eggs/sperm survive this process. That's one way to select them.

If older father choose to do IVF even if the pregnancy can be achieved through normal means, the embryos can also be screened for all the mental disorders mentioned here. Technology will improve. There will be more and more genetic data on all mental disorders.

This is a problem that can be solved with more money and technology. Using sperm frozen in your 20s might not be worth it when the resulting embryos all go through the same screening process.

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The distance in medicine between "may" and "does" is a distance of hundreds of miles.

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