LONDON - The rules on embryo research in the UK will be relaxed to allow stem cells to be harvested for research, after members of Parliament (MPs) voted 366-174 for the change.

The move will involve updating the 1990 Human Fertilization and Embryology Act, which already allows embryos up to 14 day old to be used for research into infertility.

The health minister, Yvette Cooper, denied that the change would open the way to human cloning, saying, "Human reproductive cloning is illegal and must stay illegal." She told MPs the change was a "sensible extension" of the existing law. There is a strict regulatory framework and researchers are limited to working on embryos up to 14 days old.

The relaxation of the law is opposed by pro-life groups and some religious leaders. The government gave MPs a free vote on the grounds it is an issue of conscience.

Cooper said the change would give hope to people with incurable conditions such as stroke, Parkinson's disease and muscular dystrophy. "There are immense potential benefits from allowing research to go ahead, particularly for those suffering from dreadful chronic disease."

PPL Therapeutics plc, the company that cloned Dolly the sheep, has filed patents on a process for deriving unlimited numbers of mammalian pluripotent stem cells without using embryos. Shares in the company fell by 12.5 pence to #1.95 after the vote because investors believed the relaxation of rules on embryo research devalued PPL's technology.

In an unusual step, PPL made a formal announcement to the London Stock Exchange, claiming investors "may have misinterpreted" the effect that the changes to the embryo research bill would have on the company.

PPL, based in Edinburgh, Scotland, said it welcomed the vote. It opens the way for research to take place on the conversion of human stem cells into, for example, pancreatic islet cells, at the same time as PPL develops its own technology for producing stem cells. "The combination of these two courses of action will shorten the time to produce beneficial solutions to many human diseases," it said.

In October 2000, PPL won a US$1.9 million grant from the U.S. Department of Commerce to fund its work on deriving nonhuman primate and livestock stem cells by "rescripting" the genetic programming of differentiated cells.