An international panel of scientists has said that while technology that will allow human egg and sperm cells to be grown from stem cells could be here in five years, the prospects of gay and lesbian couples having children that are genetically theirs are slim.

The report from the Hinxton group of stem cell researchers said that because women have two copies of the X chromosome but men have one X and one Y, there are no circumstances they can forsee an entirely same-sex baby.

In January a research team at the University of Newcastle created primitive sperm cells with female embryonic stem cells, leading to reports that same-sex couples may soon produce children with both their genes.

The Y chromosome carries genes vital to sperm production and turning female cells with two X chromosomes into sperm seems science fiction at present.

However, for infertile people the new breakthoroughs offer real hope.

“It would be very difficult to get eggs from XY cells, and even more difficult to get sperm from XX cells – my own view, indeed, is that the latter is impossible,” Professor Robin Lovell-Badge, of the National Institute for Medical Research in London, a member of the group’s steering committee, told The Times.

The Human Fertilisation and Embryology Bill is currently before the House of Lords.

The government may reintroduce a clause that would allow the use of eggs and sperm created from stem cells.

The Bill already allows for two same-sex partners to become the legal parents of a child created through donated eggs, sperm or embryos.

At the moment if a lesbian couple have a baby, one partner has to formally adopt the child in order to be a parent, even if the child is conceived through a fertility clinic.

The new rules would mean that civil partners will automatically become the legal parents of the child, even if the child is conceived ‘informally’ ie: not through a clinic.

The two people named on the birth certificate would also be legally responsible for the child.

On dissolution of a civil partnership the current law allows the courts to consider maintenance payments for the child.

DIY sperm donation will still be legal but under the proposed laws the non-birth mother not in a civil partnership could not be on the birth certificate.