I don't see how bringing a life into this world, that exists in this universe that operates the way it does, can be a good thing done for the sake of that life.
This is inherently somewhat nonsensical, I know. How does a person who does not exist benefit from beginning to exist in the world? I don't think there is any benefit to them. I think all life brought into the world is ultimately done for reasons that are never truly for the sake of the individuals being born.
People have kids for "their legacy," because they want the experience of being parents, for the "future of humanity," because they want someone to take care of them when they get old, or whatever of any other reasons.
If the person who does not exist is "fine" in some sense, much like I consider that before I existed, well I didn't exist, I don't think I was in any kind of state of suffering or "longing" to be born into existence, then for what possible good reason for the sake of that individual would people choose on behalf of that person that they ought to exist because "it's better for them?"
I don't think there truly are any good reasons that can be argued.
If people are somehow "worse off" for not existing, then we would need to consider that there are infinitely many people who don't exist and will never exist, if the number of humans ever born will only be a finite number. We would have to think that there are infinitely many people who are in some kind of negative state because they will never exist on earth to... what, eat some ice cream, work a job, go for walks, argue with others, get sick, and die, among other things done in human life?
I don't think so.