Scientists have found that a man's fertility could be restored by the growing of early stage sperm from a skin sample.
Research evidence suggests that adult cells, such as those of the skin, can be induced to return to a more primitive state and then turned into different cell types.
To see if it was possible to produce sperm cells, a team at the University of Pittsburgh School of Medicine in the US grew stem cells from skin samples and found they were able to generate key cells, including early stage sperm cells.
It is hoped the technique could help men who had cancer during childhood become fathers, as infertility can be a side effect of some cancer treatments.
Dr. Charles Easley, the study's lead author, said: "Sperm can be banked for future artificial insemination procedures, but that does not help some patients, such as pre-pubertal boys.
"There are procedures to store testicular tissue prior to cancer therapy, but men who didn't have the opportunity to save tissue are permanently sterile, and so far there are no cures for their sterility."
The scientists say their findings show it might one day be possible to restore fertility for sterile men with an easily obtained skin sample.
"No one has been able to make human sperm from pluripotent stem cells (stem cells that can become almost any cell in the body) in the lab, but this research indicates it might be possible," Dr. Easley said.
"This model also gives us a unique opportunity to study the molecular signals that govern the process, allowing us to learn much more about how sperm are made. "Perhaps one day this will lead to new ways of diagnosing and treating male infertility."
The process is likely to raise concerns in some quarters however, as critics are wary of creating human life through artificial means and stem cell research remains controversial.
The latest development comes after British scientists claimed earlier this year to have made a major breakthrough by creating brain tissue from human skin.