Embryologist have produced - for the first time - sperm created from embryonic stem cells which give rise to live offspring. The experiment resulted in the production of six adult mice (from sperm derived from these stem cells).
If we understand this we can treat infertility in men.
Due to very low success rate and the mice’s suffering of genetic abnormalities (as well as the ethical issues) the prospects to treat infertile men is still far off.
In the future, men with fertility problems might be able to have their own stem cells harvested using a simple testicular biopsy, matured in the lab and then transplanted back.