I absolutely agree with you; it's a ridiculous statement that would only have harmful results if enforced. Having and raising children with the right person can be a wonderful thing, but forcing it to happen no matter what isn't the right way to go about it.
I went along with his logic to give him a chance to clarify what he was saying, so that I would be able to explain to him in more detail exactly why his opinion is wrong; but his reply was so disappointing that I don't even know what to say. He didn't address anything at all; turns out he was just talking nonsense. Now I'm not only pissed off, but also disappointed that the origins of his perspective were nothing but ignorance, rather than anything I could actually learn something from to refine my reasoning.
Oh well, there's no need for me to get so worked up about it. I just hope people come to understand these things better in the future. And I do understand how his own experiences could've led him to such a conclusion, so I'll hold back in judging him too much for it.