I'm the opposite; I think it's good to have kids but I personally don't like kids and do not have any (and at 40, it's increasingly likely I never will).

Having children is a very multi-factor decision, so I doubt anyone forgoes for just that one reason, and a pretty impersonal one at that. Still, it has to factor in, even at a subconscious level for those who go childless or have fewer children.

Actually I'd argue that you can see this in action in birth rates right now in the USA and across most of the developed world. Having children is expensive. The standards for care and education keep getting higher. The available time for childcare is decreasing. It takes more and more education to be a fully participating adult member of society. That's a clear market signal to have less children and people are responding. The birthrate continues to fall and is below replacement in many countries, including the USA.

As a species, we appear to be regulating ourselves to prevent a catastrophic overshoot.

"genetic line" -- I mean, it's not like you're the pharoh pumping out 100s of children while subjugating those eunuchs.

Also, in a world of 10 billion peoople, it's not like any given individual has much precious DNA to pass on.

I have one daughter and I'd love her to have a sibling, but for various reasons I don't think it's going to happen, which kind of makes me sad, but not because I won't pass down my "line".

Just focusing on one small area of human achievement - there was just one single Chopin, Beethoven, Bach and Mozart. Unlike in science, no reason to suppose one of these composers 'would have come along anyway'.