Swiss voters endorsed restrictive legislation on stem cell research Sunday that forbids the cloning of human embryos and put Switzerland on a par with some other continental European countries.

  With all Swiss regions reporting, 66.4 percent of those voting had approved measures that allow scientists to extract stem cells from unwanted embryos to use in research into diseases, as in the Netherlands and Spain.

But the rules, which were approved in one of the country's regular referendums, are not as liberal as those in Britain or Belgium, where cloning to extract cells is allowed.

Supporters say stem cell research offers the chance to better understand conditions such as Parkinsons', Alzheimers' or diabetes and so come closer to developing treatments.

"It's a very restrictive law but it allows us to continue our work," said Yvan Arsenijevic, a scientist specialized in adult stem cells at the Jules Gonin hospital in the Swiss city of Lausanne.

"We, the scientists, were the ones who were seeking to have this restrictive law in place because there are potentially huge ethical problems with research on stem cells," he said by telephone.

Opponents, including Christian doctors and the Greens, want to ban research on human cells arguing that it involves taking human lives as the embryos are eventually destroyed.

"People had trouble expressing themselves on such a difficult issue. For us the debate on the ethics will continue," said Ueli Leuenberger, National Council member and vice-president of the Green party.

Stem cells are master cells of the body as they can develop into other cell types. Stem cells from embryos are more flexible than those found in adults and researchers hope to use them to generate replacement cells and tissues.

While U.S. lawmakers grapple with national legislation, EU countries have adopted differing laws, against which Switzerland's proposals appear relatively conservative.

England and Belgium both grant licenses to clone human embryos as a source of the cells. The Netherlands, France, Denmark and Spain allow research on embryos left from over artificial reproduction.

Germany and Austria allow research only on imported cells.

Supporters in Switzerland, home to drugmakers Novartis and Roche, said it would be a long time before stem cell techniques would be applied in pharmaceutical laboratories but said the industry would benefit indirectly as universities and research institutes pursue their work.