In the United States, between 10 and 15 percent of couples are infertile, according to the Mayo Clinic.

Scientists in Spain are working to help those couples. In a new study, published this week in Scientific Reports, scientists reported they’ve transformed human skin cells into germ cells, what Popular Science described as the “precursor to sperm or eggs.”     

“What to do when someone who wants to have a child lacks gametes (eggs or sperm)?” said Carlos Simon, who is the scientific director of Spain’s Valencian Infertility Institute, to Agence France-Presse. “This is the problem we want to address: to be able to create gametes in people who do not have them.”

According to the media outlet, the research was inspired by Shinya Yamanaka and John Gurdon, who both won the 2012 Nobel Prize in Physiology and Medicine.

The duo discovered that mature cells could be reprogrammed into immature cells, and develop into different tissues throughout the body. In 1962, Gurdon successfully showed that the immature cell nucleus of a frog’s egg cell could be replaced by a mature intestinal cell and still develop into a tadpole. Subsequently in 2006, Yamanaka discovered a mice’s mature cells could be reprogrammed into pluripotent stem cells, which develop into the body’s different cell types.  

Using the aforementioned techniques, researchers showed that induced pluripotent stem cells could be obtained from human skin cells.

In Simon and colleagues’ study, the researchers introduced stem cells (formerly human skin cells) to six genes that could influence its development. After a month, some cells transformed into germ cells. “The germ cells need to be implanted into a living organism to develop fully into sperm,” according to Popular Science. “So far, the researchers haven’t been able to do so efficiently.”

While it’s a step in the right direction, the researchers noted much more research is needed. If successful, it will still be quite some time before a technique becomes publicly available, as such techniques often face legal constraints, according to Agence France-Presse.