I think in both cases, a line gets crossed when people start hating the kids themselves. I'm not talking about having an aversion-- some of them genuinely hate kids. Even if I believed it were an atrocitious act to bring children into this world, even if I were to find children unpleasant(1), it's not the kids' fault.

(1) Oh hi! 👋 You saw my footnote! Just wanted to make clear I'm talking about a hypothetical person here. I personally like kids and don't find them unpleasant. Just making sure you know that so we don't start a pointless argument. Have a fantastic day!