I always find it funny the genetics argument or the "I'm a dopamine addict!" just how they are framed with fairly modern scientific language.

Personally, legacy is but another grasping of the ego. It is meaningless and is most used as a justification to be selfish. I think kids are beyond that, it isn't something that is rationalized, it is just a means of life. And that is cool. I'm not pro or anti natalism, it all just seems to be a case of some people clinging to concepts and ideas just a little too strongly. But ultimately it has the same amount of meaning as a single ant that died a million years ago.

Also what if you cannot create genetic legacy?

Meaning, when applied broadly like that is rather meaningless. In “what is the meaning of life?” the word meaning in that sentence is completely nonsensical. That being said, most people would prefer the world to be shaped in a particular way and a large part of how the world is shaped comes down to normalized cultural and societal expectations. If you don’t voice your opinions on how you want the world to be shaped or agree to be silenced, then the world will probably not be shaped the way you want it to. I want the world to be shaped a particular way and every interaction I have including this minor comment thread is one step in that direction just like everyone else.

Within my world view, if you cannot create a genetic legacy, you have failed at a key aspect of life.