French scientists have grown mature sperm cells in a lab for the first time in history. In two to four years, the breakthrough technology could be ready to help young male cancer patients and infertile men produce their own biological children, the scientists claimed, according to The Independent.

The team, led by Kallistem scientific director Philippe Durand, was able to grow mature sperm cells from rat, monkey and humans successfully, something that scientists have been attempting to do for about two decades.

"We have completed spermatogenesis - the production of mature sperm cells - in vitro using a bioreactor," Durand told The Independent. "We have done it in three different species, rat, monkey and human, which has never been done before."

Durand refused to give further details about the study because it has not been published yet, but according to him, the team was able to create "a meaningful amount of mature sperm that could be of use clinically."

The process involved collecting biopsies from the testes of six infertile men. The cells were then cultured in a bioreactor until they became mature sperm cells.

At present, there are 15,000 young male cancer patients worldwide who have lost their fertility to chemotherapy, and there are 120,000 infertile men who do not respond to IVF technology. The scientists said their research could help these male patients to have their own children.

"This breakthrough opens the way for therapeutic avenues that have been eagerly awaited by clinicians for many years," the French national centre for scientific research (CNRS) said in a statement.

However, some scientists are skeptical of the researchers' claims.

"We are not there yet," French infertility expert Nathalie Rives told the Daily Mail. "Before this technique can find any practical application, it must be proven to work with cells from the testes of prepubescent boys and men who have trouble generating sperm."