Scientists Grow Human Livers in Lab Miniature versions created with stem cells By John Johnson, Newser Staff Posted Oct 30, 2010 5:43 PM CDT 8 comments Comments File photo. Scientists have used stem cells to grow human livers in a lab. (AP Photo/Paul Sancya, File) (Newser) – Scientists have grown human livers with stem cells, the BBC reports. The downside is they're really small, about the size of walnuts, and it will take lots more research and probably at least five years before the development is more than just a joke to forward to heavy-drinking friends. "Not only must we learn how to grow billions of liver cells at one time in order to engineer livers large enough for patients, we must determine whether these organs are safe to use," says the lead Wake Forest researcher. It's still being hailed as a breakthrough. Scientists took livers from ferrets and stripped away everything but the collagen structure with, as the Telegraph explains, a "mild detergent." Then they introduced the human cells, and the livers soon began growing and functioning like human organs. "Whilst 'off the shelf' new livers are clearly still a long way off, this work gives a glimmer of hope that this is no longer just the stuff of science fiction," says a UK researcher unaffiliated with the work.