In 2016, scientists at the Institute of Zoology at the Chinese Academy of Sciences produced viable mouse sperm from stem cells. To do this, they extracted stem cells from mice and introduced them to testicular cells from newborn mice.
Qi Zhou and Xiao-Yang Zhao, who led the experiment, also exposed the stem cells to several chemicals involved in sperm development. This includes testosterone, a hormone to induce follicle growth, and a growth-inducing hormone from the pituitary gland.
In about two weeks, the scientists had developed fully functional sperm cells. They implanted the sperm into viable eggs and transferred the zygotes to female mice.
Nine mouse pups were born out of this experiment, some of which later reproduced on their own. Though still not as efficient as artificial insemination using natural sperm (3 percent success rate compared to 9 percent), this research holds promise for future fertility treatments.a