If you've been laughing at those Neanderthal presidential candidates who still don't believe in evolution, it's time to sober up. Every serious scientist knows we evolved from animals. The question now is whether to put our DNA and theirs back together. We've been transplanting baboon hearts, pig valves and other animal parts into people for decades. We've derived stem cells by inserting human genomes into rabbit eggs. We've created mice that have human prostate glands. We've made sheep that have half-human livers. Last week, Britain's Academy of Medical Sciences reported that scientists have created "thousands of examples of transgenic animals"...