Stem cells in mother's breast milk may be able to develop into a range of different tissues in the offspring, including the brain, liver and kidneys, scientists have found. Previous research has found that human breast milk contains a kind of stem cell but it was not known whether these cells do anything useful for the baby. In a new study, presented at the National Breastfeeding and Lactation Symposium here last week, researchers said that in mice, breast milk stem cells cross into the offspring's blood from their stomach and play a functional role later in life. Foteini Hassiotou at the University of Western Australia and her colleagues created genetically modified mice whose cells contain a gene called tdTomato, which makes them glow red under fluorescent light. The females mice were mated but then after giving birth were given unmodified baby mice to suckle. So any red cells that ended up in the pups must have come via the milk, 'New Scientist' reported. When the offspring reached adulthood, red cells were found in their blood and many of their tissues, including the brain, thymus, pancreas, liver, spleen and kidneys. Using other techniques, Hassiotou's team also found that the stem cells had developed into mature cells. The ones in the brain, for instance, had the characteristic shape of neurons; the ones in the liver were making the liver protein albumin, and the ones in the pancreas were making insulin. "They seem to integrate and become functional cells," Hassiotou said. The finding that breast milk stem cells are capable of making different tissues makes it more likely they could be used for therapeutic applications, said Hassiotou. Breast milk stem cells seem to have less capacity for unlimited cell division than embryonic stem cells. But that's actually a good thing, noted Hassiotou, adding they do not form tumours when injected into mice, for example, so they may be less likely to trigger cancer if used to treat people.