Stem cells could grow both eggs and sperm, scientists claim

The desperate shortage of donated eggs and sperm for fertility treatment could be solved after British scientists found that they can both be grown from laboratory stem cells.

But some experts warned that the discovery raised serious ethical questions, saying that it could mean that a single man could provide both the sperm and egg for fertility treatment, making him genetically both parents [father and mother] of his child.

They also claimed that the technique came close to human cloning, although the scientists who conducted the study denied this.

Researchers from the Centre for Stem Cell Biology at the University of Sheffield studied six human embryonic stem cell (HESCs) lines taken from very early embryos that had been donated by couples undergoing IVF treatment in Britain.

HESCs are the building blocks of human development and turn into any type of cell, such as organs or tissue.

But scientists have not been clear about when HESCs begin to differentiate into primordial germ cells (PGCs), which are the ancestral cells that eventually form sperm and eggs.

The Sheffield researchers allowed the human stem cells to develop into collections of cells called embryoid bodies, and then tested them to see which genes were active in them.

Within two weeks of development, a very small proportion of cells in the embryoid bodies had begun to "express" some of the genes found in PGCs. Some also began to express proteins that are only found in maturing sperm, suggesting that human stem cells can develop into PGS, and eventually eggs and sperm.

Dr Behrouz Aflatoonian, who led the research, said: "Ultimately, it might be possible to produce sperm and eggs for use in assisted conception treatments.

"This is a long way off, and we would have to prove that it was safe because, for example, the culture process may cause genetic changes.

"For some men and women this would be the only route for producing sperm and eggs.

"It would not be reproductive cloning as fertilization would involve only one set of gametes produced in this way, and therefore a unique embryo would form."

One in seven couples in Britain experience fertility problems, and around 7,000 people a year are treated using donated eggs or sperm.

Some couples are able to use their own eggs or sperm, but others with particular fertility problems are reliant on donated samples. Only 250 men and 1,100 women donate their sperm or eggs each year, meaning there is a drastic shortage and long waiting lists at fertility clinics across the country.

There are also concerns that fewer people may be prepared to become donors after the rules governing anonymity changed, making it possible for children born as a result of fertility treatment to obtain details about their biological parents.

-INDEPENDENT