Developing therapies from human embryonic stem cells is under threat in Europe, say scientists.

In a letter to Nature, they express “profound concern” about moves at the European Court of Justice to ban patent protection for embryonic stem cell lines.

A law officer argues it should be unlawful to allow patents where research involved destroying embryos. The judges are not bound to follow the advice but frequently do so.

Human embryonic stem cells have the potential to turn into any tissue in the body.

Many scientists are excited by the prospect of using stem cells to create healthy replacement cells to treat disease.

After more than a decade of research the first clinical trials are underway in the US.