One of the consistent complaints about modern science is that it often progresses faster than society's ability to ensure that its potential applications are properly regulated. Frequently it is the scientific community and its industrial counterparts who are seen as responsible for this state of affairs. But in the case of last week's dramatic announcement of a major breakthrough in the culture of human embryonic stem cells (see page 104), political authorities — and in this case, the US Congress — have only themselves to blame. Maintaining a ban on such research with federal funds, while leaving the private sector totally unregulated, has ended up with the worst of both worlds.

Geron, the company that has negotiated licences to the research results in question, has made it clear that the use of the technology will be regulated — but, given the political vacuum, by them, not by any democratically representative body. Strict conditions — as are increasingly required in other areas of biomedical research (see above) — will have to be met by anyone seeking to use the stem cells for research. Some of these ethical requirements will be desirable, but they should not be left in the hands of a commercial company.

If there was ever a good time to reopen the congressional debate on the ban on federally funded research on embryos, it must surely be now. It is important that the arguments of those in favour of such a ban are given due respect — and, furthermore, are not trampled into the dust as the public clamours for the therapeutic dividends that Geron's new techniques offer. But it is also important that the conditions under which the research and its applications develop are subject to the broadest public scrutiny and consistent regulation. In the current circumstances, that cannot happen. Changing the law to make this possible is the only sensible — and responsible — way forward.