Science can tell us what can be done in principle, but it is then a matter for public debate as to what should be done. And ultimately, it is a role for politicians to decide the answers.

People go on exploration; they're trying to find places that weren't known before. But it is an inevitable fact of research, as is in any other form of exploration of the unknown, that some people find they go down a dead end.

The European Parliament must send a clear sign that it recognises the importance of embryonic stem cell research.

Mark Walport Quotes