Suffice to say I won the argument, me being a 170 IQ master of hope and the universe and whatnot, but arguing him felt like shooting fish in the barrel.
The crux of his argument came down to believing that the chance of giving birth to someone who could end up a pessimistic fuckup (like himself, by his own admission) was too high to take the risk of inflicting that on a prospective other. He said the chance of giving birth to a fuckup was 50/50. I said that I believe in bad apples, and theres no way to quantify the number of bad apples that show up in the barrel, but I said it was probably closer to 10%. He didn't acknowledge this point.
I tried to get a straight answer out of him about whether or not he believed in personal responsibility, specifically the personal responsibility of any person brought into this world to fight for a happy life for themselves, and he kept pussyfooting around the answer, essentially saying that theres a randomness factor involved in whether or not a person is capable of happiness. I said that it wasn't his personal responsibility to worry about whether or not any child he brings into this world is a fuckup, its only his personal responsibility for him to avoid that. He cycled back to his previous point without acknowledging this.
He offhandedly mentioned the point of "what if I give birth to a kid with downs syndrome?" I wish I would have called him a eugenicistic ableist fascist nazi and what not, the impact of that strawman being compounded by him being a shitlib, but I didn't. All I said is that if I ended up having a kid with downs syndrome, me and that kid would go to so many fucking baseball games together.