First human-pig chimeras created, sparking hopes for transplantable organs - and debate
Piglet (Shutterstock www.shutterstock.com)

Pig embryos that had been injected with human stem cells when they were only a few days old began to grow organs containing human cells, scientists reported on Thursday, an advance that promises - or threatens - to bring closer the routine production of creatures that are part human and part something else. These human-pig "chimeras"…