One day, man's job in the family may be just to cut the lawn and change the light bulb when necessary. This is because researches like this one made at the University of Newcastle could put them out of the reproductive business.

The team led by Professor Karim Nayernia has now created spermatogonia (the cells from which sperm cells come, in other words, proto-sperms), starting with human female bone marrow cells! Previously, the team had managed to do this by starting from male bone marrow. In this case, the lesbian couples would conceive their own children, possessing DNA 100% coming from both women, not 50% from one of them and 50% coming from one male sperm donor. Sperm cells would be created from one partner and they would fertilize the partner's ovule.

Men have one X sex chromosome and one Y sex chromosome, women two X chromosomes. The Y chromosome is believed to contain several genes that are crucial for producing sperm, hence a large skepticism towards the fact that female stem cells could be manipulated to make sperm cells.

The issue faced by the research is if this resulting embryos are viable and healthy, as the scientists must induce in the achieved spermatogonia a meiosis division that would share in a 50% proportion the DNA material into the resulting daughter sperm cells. Otherwise, the lab-made sperms would have too much or too less DNA, and the resulting embryos would not be viable.

"I think, in principle, it will be scientifically possible," Nayernia told New Scientist.

Nayernia has already solved this problem with sperm cells achieved from male cells. In 2006, sperm cells achieved by its team from embryonic stem cells were used to impregnate mice females. Of the resulting 7 pups, one died and the other 6 had health problems.

Others doubt that men could be discarded so easily.

"The presence of two X chromosomes is incompatible with this. Moreover they need genes from the Y chromosome to go through meiosis. So they are at least double-damned," said Dr. Robin Lovell-Badge, a stem cell and sex determination expert at the National Institute for Medical Research, Mill Hill, London.