My cousin has Down's Syndrome. Plus, I worked for the ARC, which serves people with developmental disabilities such as Down's Syndrome, for 5 years. I worked in a group home with a middle aged man with Down's Syndrome and a middle aged woman with Down's Syndrome. They both had jobs. They both had hobbies and interests. And friends. They were both interested in the opposite sex. And they both seemed to derive at least as much joy out of life as many "normal" folks I've met.
If we all treated each other like many of those with Down's Syndrome, this world would be a better place.