[xico]

One of the (maybe more) obvious downside being the increase in mutations this brings, in the order of 1 full generation of mutations for every decade the fathers are older for instance. There are plenty of studies on these issues, notably paternal age genetic disorders and "selfish genes", as well as increase of autism, schizophrenia, mendelian disorders, ....

https://www.sciencedirect.com/science/article/pii/S001502822...

[Rury]

Increased mutations/mutation rate is not necessarily a downside. Mutations aren't inherently bad, they can be beneficial, and the vast majority actually have no effect whatsoever, as the majority of our DNA is never used. But yes increased mutations means increased chances of bad mutations happening even if it also means increased chances of good mutations happening. Anyhow, it may put evolutionary pressure for longer lifespans. Studies involving fruit flies, and selective breeding them as old as possible for successive generations, show that can be the case. And other studies involving natural selection show that high mutation rates are a good thing (ie they help species survive), when environmental change is high (but high mutation rates are detrimental if the environment remains stable).

[ralusek]

Probably a good thing to speed up the evolutionary landscape during these rapidly changing times.

[seanhunter]

It would not speed up evolution at all.

I remember seeing a talk by Steve Jones[1] where someone asked a question like this and he said the human species has basically not evolved at all for I forget how long he said but it was at least hundreds of thousands of years. He said specifically if you took the children of someone like this dude[2] and put them in a modern school system they would not perform noticeably differently in any way from a modern child as long as they had decent food etc all the other benefits of modern society.

[1] https://profiles.ucl.ac.uk/7056 (emeritus professor of human genetics and evolution at university college London and the author of a fantastic book on the subject called "In the Blood")

[2] https://en.wikipedia.org/wiki/%C3%96tzi