Publication of a research paper on creating sperm cells from embryonic stem cells has created the usual media furore, complete with mostly uncritical hype about what this technology can actually achieve and a failure to ask scientists the really hard questions.

Not being a pro-lifer I have no problem with the use of embryonic stem cells in basic research. However, the idea that sperm cells produced from embryonic stem cells in a laboratory could be used in fertility treatment is a dangerous and unethical technological fantasy. Like the idea of “therapeutic cloning”, what seems simple in theory will in practice prove practically impossible, precisely because it is so unnatural. Ten years ago we saw huge quantities of hype generated about the idea of curing disease through creating stem cells from cloned embryos and using them to generate tissues for transplantation. Yet no-one has even succeeded in getting a cloned human embryo to divide more than a couple of times, and the biotech industry and nearly all stem cell scientists have abandoned the idea. I suspect that the idea of sperm from stem cells may suffer the same fate.

The problem with all techniques of artificially manipulating human reproductive cells in the laboratory is that they tend to generate epigenetic errors (i.e. errors in whether key genes are turned on or off) which lead to severe metabolic and physiological problems in the cells and animals derived from them. This is best known with cloning, which is perhaps the most unnatural technique as it involves completely bypassing the normal processes of production of sperm and eggs, and also forcing adult cells to completely reverse their history of development in a single leap. It is not surprising that this produces many deformed and dead animals, but we now know that even the least manipulative technique, IVF, also produces some epigenetic errors at a higher than normal frequency. Thus, neither is it any surprise to hear that many mice produced from sperm cells that were developed from embryonic stem cells by the same researchers had deformities and died shortly after birth. This risk would also apply to any human babies produced through these techniques, and any attempts to treat infertility in this way would be highly ethically questionable. Sadly, in many countries where there is little regulation of reproductive technology the risks to children seem to be little barrier to the constant innovations of the entrepreneurial fertility industry.

When we examine Professor Nayernia's proposal however, the situation looks even worse. In order to create sperm from a man who was infertile for non-genetic reasons he proposes to take a skin cell from the man and, using what he calls the “pioneering stem cell technique of somatic cell nuclear transfer” (i.e. cloning), create a cloned embryo, which could then be used to extract stem cells. Thus, on top of the epigenetic risks of creating artificial sperm he adds a second layer of epigenetic risk, from the cloning step. It should be also be noted that sure a procedure could not overcome the fertility problems of men whose infertility had a genetic cause, since the embryonic stem cells produced from the cloned embryo would have the same genetic flaws, and would be unlikely to be capable of producing sperm in the laboratory.

So, as is often the case with stories about stem cells, the reality turns out to be very different from the speculative promises of scientists and the hopes that they generate in the minds of patients. People sometimes argue that many medical technologies are very imperfect at the early stages and need years of work to make them safe and effective, and that we should therefore allow this line of research to continue. However, there is an important distinction between techniques which attempt to reproduce something that happens naturally, such as IVF and those which try to force nature against its grain, such as cloning. It is precisely because cloning is so unnatural that it is so inefficient and produces so many errors. We have to judge the likelihood of success of different technologies, because there is a limited amount of money for research, and we cannot fund everything. In my view, pursuing this line of research would be a waste of taxpayers' money, which could be far better spent on discovering why there is such an epidemic of infertility in our society, and developing preventive public health interventions. It is certainly far too early to be issuing the kind of knee jerk calls for changes in legislation to allow this technique, which where emanating from Newcastle and from Dr Evan Harris MP.

But while the reality does not match the hype it is interesting to look at what is driving this research and why many people have such strong reactions to it. There seems to be something about embryonic stem cells that encourages normally cautious scientists to pursue extravagantly ambitious schemes such as this. The power of embryonic stem cells to generate any cell type in the body seems to create a sense of excitement and limitless power. It is as if scientists feel that they have their hands on the fountain of life. Perhaps it is this intoxication with their power that leads scientists to think that they can, at will, force nature against its grain and leads them, as in the case of human/animal hybrid embryos, to forget their basic biology lessons (HGA briefing on hybrid embryos).

With embryonic stem cells the possibilities for manipulation seem limitless. But scientists should not be surprised when their fantastic schemes provoke people to cry that what they are doing is unnatural. For, just as with cloning and human/animal hybrids, those ordinary, scientifically uninformed people are actually dead right and, what is more, it is the unnaturalness that is at the root of why it is unlikely to work.

Although their concerns are often poorly articulated, people are also right to say that the ongoing drive to bring the entire cycle of human reproductive biology into the laboratory does raise truly existential issues. For if reproductive biology does not tell us who we are, it does determine what we are. Much of the media discussion has focused on the idea that this might lead to 'men becoming redundant'. As with cloning, and the fears of armies of cloned soldiers, the point is not to take such scenarios literally, but to look beneath the surface at what the fears are really about. The scientific drive to abstract the whole of the human reproductive life cycle from its context of actual human bodies is just an example of the deep dynamic of science in our society. Since the Scientific Revolution of the 16th and 17th centuries, the function of science has been to control nature and to impose order upon its random messiness, eventually to improve upon it, and ultimately to replace the need for it. What reproductive and biotechnology are now bringing home to us is that nature includes us. Thus, for the last 25 years we have seen the emergence of transhumanist/ posthumanist movements, which look forward to the evolution through technology (including bio-, nano- and information technology) of posthuman beings (entities?). Feminists have been arguing since the 1970s that reproductive technology is an attempt to control and appropriate women's fertility, which aims ultimately to end the reliance on the female body for production of children, through artificial wombs. Now, it seems it is men's turn to feel this anxiety.

These issues cannot be waved away as insignificant compared to the medical benefits of research, especially when those benefits are in any case so dubious. Critics of reproductive technology are often told that they are being “emotional”, yet in fact it is often the enthusiasts for science and “progress” whose language is steeped in emotional blackmail concerning sick children and the despair of infertile people. I do not doubt the sincerity of these scientists in wanting to help infertile people, but perhaps they should also examine their own emotions concerning their desire to manipulate nature, and their refusal to accept limits imposed by biology.

David King