Fragile X is the leading cause of mental retardation and is the most common genetic cause of autism. Scientists were able to reverse the damage caused by Fragile X in mice by ihibiting a brain chemical called PAK.

http://news.yahoo.com/s/afp/20070627/hl_afp/ushealthautism

I’m an animal lover as much as the next person, but this study is exactly why we need to continue animal research.