[awkwarddaturtle]

That could be true, but older fathers also have more defective genes, are less able to play with their children, etc. The children are just genetically "weaker", have more physical issues and participate in far less physical activity because their father is so old.

This is anecdotal evidence but one of my friends had a very old dad. He had issues which forced him to wear bifocals and hence he didn't participate in sports. And his father was 60 when he was conceived so his dad didn't play catch with him or get him to try out for little league or play basketball with him.

So instead, he stayed home mostly and used the computer and got into "geeky" stuff.

The father's other children he had when he was younger are all very active, athletic, etc and none of them have to wear bifocals, etc.

I got into sports because my dad played catch with me and encouraged me to play sports because my dad wasn't old when he had me.

On the one hand, older fathers will be more established, but on the other hand, they will have more defective genes and less active/physical.

[dep_b]

It's an on/off situation. Genetic defects happen 1:100 when the mother is 40 and 1:100000 when the mother is 23.

But in 99:100 cases the kids are as healthy as the ones of a 23 year old mother.

I don't have the exact numbers but it's something in that ballpark.

It's not a weak versus strong physical thing. And it would affect mental capacities at the same rate. Geeks are usually not dumber than average.

[haihaibye]

Those are the rates for something like Down's syndrome. Gross chromosomal abnormalities are mostly determined by maternal age.

Everyone has a few mutations in protein coding regions, and the number rises with paternal age. Most mutations are neutral or harmful.

More rolls of the dice to accumulate more (likely small) damage is probably going to hurt you.

The way it almost certainly works is people who have better genes (for socioeconomic success in our current society) have kids later and these kids inherit these traits....

However it would probably be better if the dad had the kids younger.

It's also easier for denovo mutations to cause mental rather than physical problems as the brain is very complex so there's more genes used and more to go wrong.

PS I'm a 37 year old bioinformatician expecting a little geek in a few months :)

[ouid]

What do you mean by "defective genes"?

[zhemao]

Genetic mutations. As you get older, you accumulate more genetic damage, which can be passed on to children. It's fairly well-studied that children of older parents are more susceptible to genetic disorders.

[ouid]

I have two problems with your argument.

To start, I'm going to assume that, by defective, you mean unintentional, correct me if I'm wrong. This is equivalent to the assertion that there is no feasible mechanism to preventing your germ cells from accumulating damage due to age, because otherwise, if it was maladapative, AND evolution could design a mechanism for preventing it, it would have. It's been long enough since mammals started reproducing sexually.

This doesn't even make a little bit of sense though. It's clearly possible to keep the error rate constant. What's the difference between the germ cells in my body and the germ cells in my offspring's body. Why do those last longer?

As you grow older, your offspring have more genetic diversity. It seems like the accumulation of mutations is intentional for older parents. The more similar your children are, the more likely they are to compete with each other, and the older you are, the more children you are already likely to have. So I propose that this is not a defect, but rather by design.

Second, why on earth does this explain the hypothesis? Nerds are smarter on average, yes? Does it not make at least twice as much sense that smarter individuals are sexually attractive at older ages than athletic ones than reasoning that genetic defects are the thing that makes a person smart.

[haihaibye]

>> What's the difference between the germ cells in my body and the germ cells in my offspring's body. Why do those last longer?

Interesting question, I'm not sure but there is a selection mechanism with sperm creation, movement and implantation.

Ie your bad germline cells with too much damage don't make it to the next generation.

[ouid]

That's not a hard solution to replicate inside of a single organism. The fact that we haven't suggests that it isn't adaptive.

[haihaibye]

Naturally aborting a foetus due to genetic errors found in growth stagrs after combining with foreign DNA in your balls then shutting down the process and re-extract the germline cells is easy?

Why bother going to all that trouble when you can move the DNA to a new body and let the old one fall apart?

For it to have been worth it, a longer reproductive career has to pay off more than the opportunity cost of spending effort on other strategies eg aquiring more mates or investing more in your kids.

The most optimal balance is of course the DNA running around today.

[dragonwriter]

But even at fairly old ages, the levels are very low. Yes, they are several multiples of the rates at younger ages, but the base rates are also very, very low.

So, it's a real issue, but it's also very was to percieved it as much bigger than it is.

[awkwarddaturtle]

As you grow older, there are more mutations and more risks for defects.

https://www.scientificamerican.com/article/children-with-old...

[s_kilk]

This is some Phrenology-grade bullshit

[olewhalehunter]

https://rbej.biomedcentral.com/articles/10.1186/s12958-015-0...

"Effects of increased paternal age on sperm quality, reproductive outcome and associated epigenetic risks to offspring"

[awkwarddaturtle]

Not phrenology. It's science/genetics.

https://www.scientificamerican.com/article/children-with-old...

[Cozumel]

Spotted the old guy!

[dang]

Please don't do this here.