I have 2 kids with a chromosome disorder. One will likely live with us forever and the other will be able to hold a job and provide for himself. Both of them are loving caring children. How can anyone say that killing them as an infant is a benefit to them. If you asked either of them if they wanted to die the answer would be no. Where do draw the line? Either life is precious and worth protecting or it isn’t. What if you as an adult we’re in an accident and lost both legs. Should society determine whether your life is worth the effort and burden? What if you couldn’t work and had to be supported by the tax payers? Surely then you want to be murdered.
You just brought up the point I was looking for (and what I think Ethan was trying to make). Yes, there is a very steep slippery slope in this thought process. I would counter that with the argument that when a human is no longer or was never able to have a conscious thought would we still consider them human beings? We define ourselves as different from animals by our ability to have rational thought (though many segments in society challenges that ability). So if a person is no longer capable of rational thought, are they still human?
*And again, I'm not stating this because I believe in this argument, I just want to see how far down the rabbit hole we can go. I had this discussion once with another person and I wanted to see how others would counter his ideas*