Sperm from female stem cells?

British scientists have created early-stage, human sperm from female stem cells, according to a news report in New Scientist magazine. It is claimed that the research will pave the way for same sex couples to have children that are genetically their own. However, other scientists are sceptical that this procedure would ever be possible.

Professor Karim Nayernia at the University of Newcastle initially fertilised mice with sperm derived from embryonic stem cells (ES Cells) in 2006, which gave rise to seven pups, six of which survived. In more recent work, he took human male stem cells from bone marrow and formed 'spermatogonia', primitive sperm cells that can form mature sperm cells by going through a process called meiosis. Nayernia has now apparently done the same using human female stem cells, work that has yet to be published.

The next stage in the process would be to make these primitive sperm cells undergo meiosis, which Nayernia claims he has started to do. The result could be that female eggs are fertilised by 'female' sperm, thereby eradicating the need for male gametes. However, Dr Robin Lovell-Badge, a stem cell expert at the National Institute of Medical Research in London, does not think the approach it will work. He told the Telegraph newspaper that the 'presence of two X chromosome is incompatible with this. Moreover they need genes from the Y chromosome [from the male sperm] to go through meiosis. So they are at least double damned'. Safety issues have also been raised, since the mice pups in Nayernia's initial study had health problems.

A Brazilian team of scientists lead by Dr Irina Kerkis at the Butantan Institute in Sao Paolo also claim to have made sperm and eggs from male mouse ES Cells, and are currently starting to take the work into human cells. The research brings hope to people dealing with infertility, a problem that affects one in six couples, although scientists say the process is still in its infancy and treatments are a long way off.

There is also potential to use 'induced pluripotent stem cells', stem cells derived from human skin cells, as a starting point for the process. This could enable gay men to donate skin cells that would be used to create stem cells from which eggs could be formed. The eggs could then be fertilised using sperm from his partner, and placed in a surrogatemother.

Greg Aharonian, a patent analyst in the US, is trying to patent the technology behind 'female' sperm and 'male' eggs. A self-proclaimed 'troublemaker', he wants to undermine the argument that marriage should remain heterosexual because its main purpose is procreation.

The controversial developments have provoked mixed responses in the UK and US. Mike Judge from the Christian Institute faith group says that 'children need male and a female role models'. Many religious groups still oppose gay marriage. Josephine Quintavalle, from the pro-life lobby group Comment on Reproductive Ethics, says: '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'.