Fuck you/Real life moments: response to a real comment made in psych class

If I ever have a child who is diagnosed with Down syndrome, and someone asks me if I'm going to "try again" for a "second chance", they will receive a roundhouse kick to the face while getting an earful. *

This is going to be short, because I have a paper to finish tonight, but this is a response to a comment I heard in developmental psychology. In university. Where people are supposed to think. Do people think anymore, or was that just like a passing fad?
I shouldn't have to do this, but I'm going to because I'm still trying to wrap my head around it. Why would anyone say this to a parent or even at all?!By the opening paragraph people might get the idea that I would be offended as a parent if this were to happen. And if I were a parent, I would be, but for now I'm pissed off at this line of thinking because I'm human. I'm shocked and saddened that people think that babies/anyone with Down syndrome are somehow less of people than people without Down syndrome.
Asking if someone is going to "try again" for "a second chance" sounds like they have been trying to get pregnant but have not been successful with actually doing so. This is not something you say about a child with Down syndrome or any child; these children aren't somehow failures. They are human beings, but these kinds of comments dismiss this fact even if the person didn't mean it that way. It's just a horrible and mean thing to say, suggesting that a child isn't good enough- for any reason! And considering people replaceable, interchangeable and even disposable makes the future look bleak at best. 
What if people who think this way have children with Down syndrome? Being the child of someone who thinks this way must be hard. Do the children constantly wonder what it was about the older children that made their parents "try again"? How would these assholes introduce their children? "This is Dylan. He has Down syndrome, so he doesn't count. We tried again, so this is our second chance, Bethany." That's just fucked up.

This thought quickly lead to abortion in my mind and there's more opinions than people out there, so I'll just throw mine out there. I think pregnant persons should have the right to abort an embryo or fetus if that's what they choose. But getting pregnant, finding out the child will have Down syndrome and aborting the child based on this knowledge, with the intent to conceive a child who doesn't have Down syndrome shortly after? That kind of weirds me out, and I think it's because when people do that, they are saying that the child with Down synodrome just wasn't good enough for them. These are the people who one can say are "trying again" for a "second chance".

*I reserve the right to react this way in the event that someone makes these comments about other people's children