I don't care about the species, I care about the people. If someone doesn't want to reproduce, it's better for both them and the species that they don't. People only reproducing when they personally get something out of it will eventually make future generations enjoy it more. Forcing it just promotes suffering, perpetuating the cycle of unhappy parents in the long run.
This whole idea of caring about furthering our "species" is eugenics anyways. My genes make me want to be a parent, but I understand that the genes themselves don't matter for shit. I'm planning to have kids because I will enjoy raising them and helping them live full lives. If someone doesn't share this desire, I'm not gonna force my preference onto them.
Freedom and treating humans with dignity does that very job of eugenics better than the eugenics notion of pressuring people to be parents. There's no Darwinian excuse for being shitty to other people. Just be good.