Lab-Grown Egg Cells Successfully Developed Into Healthy Baby Mice -- Possible Answer to Infertility?

A team of Japanese scientists led by Katsuhiko Hayashi, a stem cell biologist at Kyoto University in Japan, has successfully grown healthy babies using egg cells that are fully-grown in the lab.

Their work, described in a paper published in the journal Nature, is regarded to be a stunning achievement and pave the way for new and better infertility treatments. The researchers were able to grow fertile mouse eggs using stem cells. After successfully creating the egg cells, the researchers then fertilized the eggs with mouse sperm and implanted into foster rodent mothers, producing healthy pups.

Their methods may look like an easy process, but it may take a lot of trial and error to be able to produce stunning results. Science Magazine reported that the methods of the Japanese scientists sometimes produce defective eggs and had a success rate of less than one percent.

At first, the scientists took cells from mouse tail and reprogrammed the adult cells to be immature stem cells. The immature stem cells were then carefully altered into egg precursor cells. These precursor egg cells were inserted to clusters of cells taken from fetal mouse ovaries and cultured for more than a month.

More than 50 mature egg cells were produced by each of the lab-grown ovaries. However, 25 percent of those egg cells have a higher rate of chromosome abnormalities compared to eggs produced in normal ovaries. The researchers fertilized some of the eggs with the correct number of chromosomes using healthy mouse sperm. The fertilization of the lab-grown egg cells produces more than 300 two-cell embryos, which were implanted into foster mothers. Out of those embryos, only 11 or just three percent grew into a full-term pup.

The possibility of creating healthy human egg cells using the method used by the Japanese researchers is still slim. There are a lot of important factors that are not yet fully understood by the scientists. These technical issues are not the only problem that hinders the production of artificial human embryos. Safety and ethical issues also arise when the topic is brought up. The chances of serious genetic flaws in the artificial eggs being passed on to generations are still high and the possibility of designer babies put the scientists hanging on the ethical line.