The morality of embryonic stem (ES) cell research is not a matter on which opinions are easily swayed. Like abortion, views are largely determined by deep-seated religious and cultural outlooks that are difficult to shift.

For some, the potential for relieving the suffering of paralysed or diabetic patients is sufficient to justify the destruction of embryos. Others who regard an embryo as a fully formed human life will always find this unthinkable. Therapeutic cloning can be seen as a valuable tool for medical research or as an affront to human dignity that will lead to cloned babies. These positions share little common ground or room for compromise.

It is thus unsurprising that different countries have reached differing conclusions about how this new field of science should be regulated. At one end of the spectrum, Germany has, in effect, made such research illegal, largely because of sensitivity about its Nazi past. America denies federal support to most ES cell work but allows it with private funds. Britain is more liberal, permitting both ES cell and therapeutic cloning under licence. China has fewer rules still. This is quite proper. US laws frustrate scientists and Britain’s upset some religious groups, but sovereign states have the right to regulate science as they see fit.

But this does create problems. As the Hinxton Group, a new international consortium of 59 scientists and ethicists, pointed out this week, medical science is rarely conducted by isolated teams confined to single countries.

It has become an international affair and global collaborations have speeded up the pace at which new treatments are discovered. The Human Genome Project is a shining example: scientists from 18 nations, including Mexico and Brazil, Britain and America mapped humanity’s genetic code far more quickly than a domestic group could have managed alone.

International collaborations like this are crucial if the promise of ES cells is to be realised. The plethora of regulatory regimes, however, means that this is not simple. German scientists, for example, are barred not only from working on ES cells in Germany but from joining legal research elsewhere. Even e-mailing informal advice or moving abroad to experiment carries the risk of prosecution.

Lax regulations can be as problematic. Many UK experts are wary of collaborating with China, where ethical guide- lines are vague. They worry that they might unwittingly end up using stem cells that have not been obtained in accordance with British standards, and jeopardise public trust in their work.

A sensible way forward is to be found among the Hinxton Group’s suggestions. It called on funding agencies and peer-reviewed journals, which each have great power to shape scientific research, to agree ethical guidelines that must be followed by all members of the teams they support or publish. This would encourage collaboration in the absence of regulatory harmony, by assuring scientists of basic rules to which prospective colleagues must adhere.

It also urged scientists to concentrate their lobbying on the right of researchers in restrictive countries to co-operate with legal work conducted abroad. While there is a precedent for criminalising behaviour beyond national jurisdiction — it is applied to sex tourists — even nations that oppose stem cell research might be convinced not to treat medical scientists in the same way.

The scientific community would be wise to listen to the Hinxton Group. It is not about to persuade governments to reach unanimous agreement on stem cell research, and there is no reason why they should. It is more important and achievable to build an environment in which collaboration can thrive, to the ultimate benefit of patients.

Mark Henderson is the Times science correspondent