Also, I'd be willing to bet that our sex drive had a decent role in evolution. Basically be strong, smart, and acquire stuff so we can put our dicks into pretty females.
I also think it's putting the horse before the cart. To some degree we don't even shape the world to have kids, we also have kids to shape the world. That is, for them to live, because we like to live. Life likes to live; it also likes to see other life thrive. That with similar genes preferably, sure, but also simply life in general.
Plus, from the perspective of genes, it makes zero difference if "my" genes or similar ones that "belong" to someone else are replicated, completely contrary to how we feel about that.... which to me is another indication that this view of life being this endless and futile struggle (harshly put, like a malignant cancer trapped in a finite universe), is more to do with cultural pathology or delusion than life itself.