I don't know so much about the extinction of the human race but a less populated world sounds good, and probably is very much needed for environmental impacts on the world. And at least a responsible and wise decision to procreate.
Most humans have sex because it feels good, they're horny, for advancement, for favors, for money, or they're drunk. Some do it because of creating a family. That can be understandable.
But what also should be considered is adoption and foster children. I don't think this happens enough and should happen the same as adopting animals.
The difference we could make in someone's already existing and probably tumultuous life where it's truly needed rather than bringing another being into population.
Then being a good parent if you're going to bring babies into this world.
Then the cycle of why someone ends up in a foster home or up for adoption because someone couldn't handle the responsibility in the first place.
And where do a lot of people end up with bad parenting? The streets, jails, homeless and unloved. All that leads to nothing positive and productive to just adding to more breaking down of society.