Imagine a world in which women without viable eggs are able to have babies using eggs created fresh from cells of their own skin. Or how about one in which two men can father their own biological child ― one with DNA from both dads.
We’re not there yet, not by a long shot. But in what Nature magazine is calling a “tour de force of reproductive biology,” scientists in Japan have succeeded in turning mouse skin cells into mouse egg cells and then using the eggs to grow normal mouse pups.
“It is a tremendous advance,” Dr. Azim Surani, a University of Cambridge stem cell expert who was not involved in the research, told New Scientist. “The idea that you can start with a skin cell and make viable eggs in culture is quite amazing.”
Though previous research successfully used skin cells to make viable egg cells, the new process is significant because it was accomplished entirely within a lab dish, Scientific American reported. Previously, immature skin-derived eggs had to be implanted into a living mouse in order to mature fully ― a more unwieldy process.
To achieve their feat, researchers at Kyushu University in Fukuoka, Japan, took cells from the tails of female mice and turned them into stem cells ― undifferentiated, embryonic-like cells that can become any cell type in the body ― by treating them with a mixture of proteins and growth factors, The Wall Street Journal reported. Then they cultured the cells alongside mouse ovarian cells to produce the mature egg cells.
To test whether eggs produced in this manner could yield offspring, the researchers fertilized them with mouse sperm and then implanted them in the uteruses of other mice. Only 1 percent of the cells led to live births, according to Scientific American. But the stem cell biologist who led the team of researchers, Dr. Katsuhiko Hayashi, said the resulting animals were healthy and fertile and lived a normal lifespan.
The same basic process might ultimately be used to restore fertility to women rendered infertile by early menopause or chemotherapy treatments. It might also allow male couples to father “two-father” babies using eggs from male skin cells ― though that might necessitate finding a way to remove the Y chromosome, Dr. Jacob Hanna, a stem cell researcher at the Weizmann Institute of Science in Rehovot, Israel, told New Scientist.
“I get one email a day from same sex couples asking me about this,” Hanna said, per New Scientist.
But Hayashi cautioned that skin-cell-derived eggs might not be suitable for use as a fertility treatment because their low quality might yield abnormal offspring. And absent a breakthrough that “accelerates the technology,” he told The Huffington Post in an email, it might take 10 to 20 years to create human eggs using the process.
Dr. Diana Laird, a developmental biologist at the University of California, San Francisco, agreed that clinical use of the technique ― if it ever comes ― would take some time.
“I wouldn’t want patients who have infertility to think this can be done in humans next year” or any other time in the near future, she told Science News.
Even if the technical challenges are overcome, the technique raises big ethical questions. For one thing, it might be used to make so-called “designer babies” whose high intelligence or other beneficial traits might give them unfair advantages over other babies.
And using the technology to create a child in any “unusual way” ― including its use by male couples ― would necessitate new regulatory oversight, Dr. Arthur Caplan, a bioethicist at New York University, told HuffPost.
Then there’s the matter of cost.
“This will be very expensive,” Caplan said. “Will this only be available for the rich? And how much do we want society to spend on this,” given that there are so many children in need of adoption?
Stay tuned!