SilasMortimer writes "Researchers from the University of Colorado at Boulder have accomplished that for which humankind has been desperate since the dawn of civilization: turning sad, injured regular mice into angry, beefed-up super-mice. Well, okay, there's no official word in the article about the rodents' emotional states, but certainly when stem cells were injected into mice with leg injuries, the muscle grew back... almost twice as big as it was before the injury [abstract, supplemental material (PDF)]. This has many exciting implications, from better healing after injuries to slowing down the aging process to a spike in the number of cases of Generalized Anxiety Disorder among cats. I, for one, refuse to perpetuate outdated memes. (But feel free to make up for the lack.)" If these mice are bred with those given previously discovered treatments to make them smarter and fearless, we might be in trouble.