Creating sperm from women would mean they would only be able to produce daughters because the Y chromosome of male sperm would still be needed to produce sons. The latest research brings the prospect of female-only conception a step closer.

"Theoretically is it possible," Professor Nayernia said. "The problem is whether the sperm cells are functional or not. I don't think there is an ethical barrier, so long as it's safe. We are in the process of applying for ethical approval. We are preparing now to apply to use the existing bone marrow stem cell bank here in Newcastle. We need permission from the patient who supplied the bone marrow, the ethics committee and the hospital itself."

If sperm cells can be developed from female bone-marrow tissue they will be matured in the laboratory and tested for their ability to penetrate the outer "shell" of a hamster's egg - a standard fertility test for sperm.

Why would lesbians want to fertilize hamster eggs anyway? I'm so confused.

That whole sex thing with lesbians is nasty anyway. They're always screaming and you have to tie them up first.