London - Scientists in Britain have claimed a breakthrough that could end male infertility by creating human sperm in the laboratory, according to a report in the journal Stem Cells and Development Wednesday. But other experts immediately cast doubt on the claim, saying that the cells did not constitute "authentic" sperm with all the necessary biological characteristics.
Researchers at Newcastle University in northern England said they had produced fully mature, functional cells, grown from stem cells from a male embryo, which they call In-Vitro Derived (IVD) sperm.
Professor Karim Nayernia, who led the research at Newcastle University and the NorthEast England Stem Cell Institute (Nesci), said the cells were observed "to split and divide and then eventually push out a tail and begin to move."
"This understanding could help us develop new ways to help couples suffering infertility so they can have a child which is genetically their own," he wrote.
Nayernia had previously undertaken similar research at Goettingen university in Germany, where stem cell experiments are illegal, as they are in Britain. He called for the introduction of laws in Britain "sooner rather than later" to control the research.
Nayernia stressed that the scientists had made no attempt to fertilize human eggs with the sperm, but insisted that the development would lead to a better understanding of why infertility happened in men, and what caused it.
The scientists said as well as being prohibited by British law, fertilization of human eggs and implantation of embryos would hold no scientific merit for them as they wanted to study the process as a model for research.
"While we can understand that some people may have concerns, this does not mean that humans can be produced 'in a dish' and we have no intention of doing this," said Nayernia.
The team also believes that studying the process of forming sperm could lead to a better understanding of how genetic diseases are passed on.
The technique developed at Newcastle involved prompting embryonic stem cells to become "germline" stem cells - cells that can pass their genetic material to future generations.
Nayernia said the research was in its early stages and more investigation was needed to decide whether IVD sperm would be safe or suitable as a fertility treatment.
He believed that in a decade such a treatment could be offered to, for example, young boys who had received chemotherapy which can leave them infertile.
However, other experts commenting on the work expressed doubt about what had been achieved.
Allen Pacey, senior lecturer in andrology at the University of Sheffield, said: "As a sperm biologist of 20 years' experience, I am unconvinced from the data presented in this paper that the cells produced ... can be accurately called 'spermatozoa'."
Professor Azim Surani, from Cambridge University, added: "These sperm-like cells made in a dish from embryonic stem cells are a long way from being authentic sperm cells."
Criticism of the research also came from ethical campaigners.
The group Comment on Reproductive Ethics said: "This is an example of immoral madness. Perfectly viable human embryos have been destroyed in order to create sperm over which there will be huge questions of their healthiness and viability. It's taking one life in order to create another."
