For the 10 to 15 percent of couples in the U.S. who are unable to have a child, scientists are working on creative alternatives to surrogacy and adoption. They’re putting little motors on sperm to help them swim better, or creating sperm from mouse stem cells. Now one group of researchers have made another leap forward—they have created germ cells, the precursor to sperm or eggs, from human skin cells. The group published its findings this week in Scientific Reports.
The researchers were inspired by the work of pioneering scientists who, in 2012, were awarded the Nobel Prize for a technique that when put under extreme stress, adult skin cells can be converted back into stem cells.
In the study, the researchers used this technique to reprogram human skin cells. Once the skin cells had reverted to stem cells, the researchers introduced six different genetic markers that would trigger particular aspects of the cell’s development. After a month, some of the stem cells divided and matured into germ cells. However, these cells must mature more before they can become full-fledged sperm cells, as the researchers intended. Unfortunately, they found that this wasn’t possible to do in the lab—the germ cells need to be implanted into a living organism to develop fully into sperm. So far, the researchers haven’t been able to do so efficiently, but they said in a press release “this is just the beginning.”
This isn’t the first time researchers have created sperm from skin cells—one 2009 study was retracted, and a similar 2014 experiment required only a week for stem cells to transform into germ cells, though those researchers used embryonic stem cells instead of those induced from skin cells.
But don’t expect to see skin-derived artificial sperm in the clinic anytime soon. Many countries still have regulations that ban the creation of artificial embryos, according to the Telegraph. Regulators are understandably cautious when it comes to manipulating the genes or development of engineered embryos, so the researchers know that for their technique to become widely accepted, they will have to do a lot more testing to verify its safety and efficacy, as they note in a press release.