Scientists were successfully able to create healthy, artificial sperm in a laboratory. A new study published in the journal Science details how scientists from the Francis Crick Institute in London, along with their colleagues from Kyoto University, made the monumental breakthrough that could lead to treatments for genetic male infertility.

Extra Chromosome

Having the accurate number of chromosomes is important in order for cells to develop normally and in good health. It also determines our sex, with females having two X chromosomes while males have one X and one Y chromosome.

However, there are certain cases wherein a male has three instead of two sex chromosomes. Whether they have two X chromosomes (XXY) or two Y chromosomes (XYY) instead of one to complete the pair, this genetic disruption is associated with interference in mature sperm formation which in turn leads to infertility. The condition is called Klinefelter syndrome, and 1 in 500 males are affected by it.

Success In Male Mice

Now, with funding from the European Research Council, Japan Society for the Promotion of Science, and Japan Science and Technology Agency, researchers have successfully developed a method which enabled infertile male mice to reproduce with laboratory-developed sperm.

Researchers first gathered ear tissue from XXY and XYY mice. They cultured the cells and then collected the resulting connecting tissue called fibroblasts which they then turned into stem cells. Amazingly, this process led some of the cells to lose the extra chromosomes.

After guiding the cells with chemical signals which prompted them to turn into sperm cells, researchers injected them into the mice's testes where they developed into mature sperm cells. With the help of assisted reproduction, the resulting sperm cells were able to successfully produce healthy and fertile offspring.

Prospects For Male Humans

In a preliminary experiment, researchers noticed that the human cells from males with Klinefelter syndrome reacted in the same way — the extra chromosomes were also lost.

However, as much as the results are very promising for males with genetic infertility problems, researchers believe that there is still much to learn in order to determine whether this process could be used in humans as well. As of now, they still do not consider it a safe method, especially since some of the male mice involved in the study developed tumors.

Further, even if they would have proven the method to be safe, the UK still does not allow reproduction of humans with the use of artificial sperm.

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