British scientists are ready to turn female bone marrow into sperm, cutting men out of the process of creating life.
The breakthrough paves the way for lesbian couples to have children that are biologically their own.
Gay men could follow suit by using the technique to make eggs from male bone marrow.
Researchers at Newcastle upon Tyne University say their technique will help lead to new treatments for infertility.
But critics warn that it sidelines men and raises the prospect of babies being born through entirely artificial means.
The research centres around stem cells – the body’s ‘mother’ cells which can turn into any other type of cell.
According to New Scientist magazine, the scientists want to take stem cells from a woman donor’s bone marrow and transform them into sperm through the use of special chemicals and vitamins.
Newcastle professor Karim Nayernia has applied for permission to carry out the work and is ready to start the experiments within two months.
The biologist, who pioneered the technique with mice, believes early- stage ‘female sperm’ could be produced inside two years. Mature sperm capable of fertilising eggs might take three more years.
Early-stage sperm have already been produced from male bone marrow.
Taking stem cells from an adult donor – possibly a cancer patient – removes the ethical problems associated with using embryos.
The race to find a cure for infertility is global.
Greg Aharonian, a U.S. analyst who is trying to patent the technologies behind female sperm and male eggs, said he wants to undermine the argument that heterosexual marriage is superior because it is aimed at procreation. “I’m a troublemaker,” he said.
Researchers at the Butantan Institute in Brazil, meanwhile, claim to have turned embryonic stem cells from male mice into both sperm and eggs. They are now working on skin cells.
If their experiments succeed, the stage would be set for a gay man to donate skin cells that could be used to make eggs.
These could then be fertilised by his partner’s sperm and placed into the womb of a surrogate mother.
Irina Kerkis, a researcher at the Brazilian centre, said this development is possible, but raises ethical questions.
Laboratory-grown sperm and eggs offer hope for those left infertile by radiotherapy treatment when they were young.
The experiments could also provide an invaluable insight into dealing with infertility, a little understood condition that affects one in six couples.
Other scientists warn however that the research is still in its infancy and any treatment is still many years away from use in hospitals and clinics.
There are also fears that children born from artificial eggs and sperm will suffer severe health problems, like the mice in the Newcastle experiments.
Couples who have children from artificial sperm created from women would be able to have girls only. This is because the female sperm would lack the Y-chromosome needed for boys.
Robin Lovell-Badge, of the National Institute for Medical Research in London, said the creation of female sperm is at least a decade away.
Josephine Quintavalle, of Comment on Reproductive Ethics, a campaign group, said: “We are looking at absurd solutions to very obscure situations and not addressing the main issue. Nobody is interested in looking at what is causing infertility – social reasons such as obesity, smoking and age.
“All these things would provide solutions which wouldn’t grab the headlines, but a lot more people would get the response they want – which is to be able to have their own children.”
Mike Judge, of the Christian Institute faith group, said the Newcastle project flies in the face of research showing that children do best when raised by a married mixed- sex couple.
“Children need male and female role models in their lives,” he added. “Yes, there are children raised by single parents through all sorts of circumstances, but when you are talking about deliberately creating children in that way, that is morally wrong.”
Debra Matthews, a U.S. bioethicist, said: “People want children and no one wants anyone else to tell them they can’t have them.”
An update of Britain’s ageing fertility laws is going through Parliament and is likely to allow the use of artificial sperm and eggs in IVF treatment – but only for heterosexual couples.
The Newcastle research also paves the way for a woman to grow her own sperm and use it to fertilise her natural eggs, creating a child to which she is both mother and father.
Similarly, a man could be both father and mother to a child created with his own sperm and a lab-grown egg. Such children would be at high risk of genetic abnormality.