They have yet to make fully functioning human sperm this way, but last year, they were able to achieve that with mouse stem cells. The obvious benefits would be for infertile men (eg. testicular cancer survivors) to create ther own sperm. But scientists caution that there's still a lot we don't know.
Experts caution that turning sperm stem cells derived from bone marrow into functioning sperm would be no small feat. "Before we get too excited about this being a new form of infertility treatment, these cells cannot as yet be made into functioning sperm, so we have no idea if they can pass 'the acid test' – the ability to fertilise female eggs as is achieved with donor sperm in IVF treatment,” says Malcolm Alison of the London School of Medicine and Dentistry in the UK.
Stem cell biologist Harry Moore at the University of Sheffield in the UK worries that sperm created from bone stem cells could have undetectable abnormalities that could cause disease in offspring. "Unfortunately, these stem cell manipulations can lead to permanent genetic changes which would make them unsafe to use especially as a potential sperm or egg,” he says.
Anyway, this seems really exciting. But as is that wasn't enough, there is another potential application of this technology.
And women may be able to use the technique to produce sperm, allowing lesbian couples to have their own biological daughters. Nayernia says that researchers have produced the same early-stage sperm cells in mice from bone marrow cells taken from female mice.
"It should be perfectly possible for fully functional mature sperm cells to be made from these female-derived cells too," he told New Scientist.
Come on, aren't you just thrilled to the bone?