fallacycop writes:
People with dawn syndrome don't reproduce.
First of all, some females with down syndrome CAN reproduce, given that the male counterpart is normal. I can't say I've heard of a case where a down syndrome male has been able to reproduce. Anyway, the offsprings have a very high chance of having down syndrome as well.
Many severe disabilities will also prevent reproduction.
While this is true, the same can be said about severe disabilities that don't prevent reproduction.
You didn't answer my question about the fact that you and me are not able to produce vitamine c. Are we unfit?
It's an inconvienience that primates have apparently been able to overcome.