> That if you’re a life form and you cook up a baby and copy your genes to them, you’ll find that the genes have been degraded due to oxidative stress et al., which isn’t cause for celebration, but if you find some other hopefully-hot person and randomly swap in half of their genes, your baby will still be somewhat less fit compared to you and your hopefully-hot friend on average, but now there is variance, so if you cook up several babies, one of them might be as fit or even fitter than you, and that one will likely have more babies than your other babies have, and thus complex life can persist in a universe with increasing entropy

In an ideal world. But in our current world I find that economical stance in the world influences amount of children more than if you’re “fit”. E.g. the poor(er) people of the world and the ultra wealthy of the world are having more kids while the middle class is having less, sure they have to meet some kind of ‘fit’ threshold but not the kind implied IMO.