A group of Japanese scientists from Kyushu University has successfully turned mouse skin cells into baby mice without the use of egg cells.

The technology skips over the usual method of fertilizing egg cells with sperm and instead uses a method to grow the cells with the necessary chromosomal pairs needed for life to begin.

This is the first time something like this has ever been achieved and not a lot of the mouse cells from the lab led to live births, according to the study first reported in Nature.

But it has some interesting potential ramifications. Though it’s early days here and we’re just talking mice for now, theoretically, the technique could help older women who no longer produce eggs to have their own, biological offspring. It could even allow two men to make a baby without a donor egg.

The study builds on the work of Shinya Yamanaka, who won a Nobel prize in 2007 for his work in stem cell research. Yamanaka showed he could program adult skin cells to make pluripotent stem cells, which could be used to make any other types of cells for use in the body — a crucial discovery in that it meant it was not necessary to destroy human embryos to grow stem cells to help with diseases like Parkinsons.

The next part of the process was to produce mature sex cells from these pluripotent stem cells — something the lead scientist in the study Katsuhiko Hayashi had tried to do back in 2012 while at the University of Kyoto. But that proved to be a lot harder. Until now, the scientists have only been able to produce something resembling egg and sperm cells and that didn’t work for making babies.

The scientists in this study found they could make mature egg cells from mouse skin if they encased it in cells taken from a part of a mouse fetus where it develops ovaries or testis. While that part of the operation helped to shape the stem cells into something more like an ovary, it could prove problematic down the line for those who might oppose using the cells of human embryos in the process of making humans from skin cells.

However, Hayashi says he’s now working on some sort of artificial reagent to replace the fetal cells.

But we likely won’t be getting any humans this way anytime soon if regulators have anything to do with it – Hayashi and his team are not allowed to even make an attempt as Japanese law forbids fertilizing engineered human cells, even for research.

And gene-editing on humans is even a thorny subject in the U.S. Where gene modification was once the wild west and some techniques supposedly produced now fully adult humans — though it’s not clear what happened to them — Federal regulators do not currently allow genetic modification of embryos.

While that’s different from actually growing embryos from your own skin cells, it dips into unfamiliar territory and will surely be up for fierce debate — particularly if it requires the use of embryonic cells to get us there.

But the process still has a long way to go. Just 3.5 percent of the cells in the Japanese study produced live births. Compare that to other fertility methods like in vitro fertilization (IVF), which has a roughly 30 percent success rate or in vitro maturation (IVM), which is successful about 40 percent of the time.

Still, the idea that we are on the brink of creating humans from skin is mind-boggling and though the scientists working on this technology in Japan can’t continue with human cells, someone is bound to pick it up and figure out how to do it, eventually.