UK scientists are objecting to a new law that would require researchers wishing to work on embryonic stem cells to obtain consent from the cells' donors.

Yesterday (January 21), 29 researchers, including three Nobel laureates, published a letter in the Times arguing that while such consent should be required in the future, obtaining it retroactively for cell lines and disease-specific tissue banks already inexistence would be impossible, since many donors were anonymous.

The requirement is part of a revised version of the Human Fertilisation and Embryology (HFE) Bill currently going through Parliament.

Another part of the bill, the Times reports, will forbid embryonic stem cell work on tissue taken from children, even if their parents consent. Parliament is debating two amendments to overturn both measures.

"We consider express consent from a gamete or cell donor is necessary to reflect the special status of the human embryo," a spokesman for the Department of Health told the newspaper.