I am sure you've all seen the pictures of a hairless mouse with a human ear on its back, grown there, I think, so that a person with an ear missing (through cancer or an accident) can have a real ear sown on rather than a prosthetic replacement.

A group of us were discussing this recently and there were 2 questions no one knew the answer to. I'd be grateful if any scientists or interested ethicists could answer.

1. Is the ear, presumably grown from stem cells, made from the genes of the person needing the ear, to remove the possibility of rejection? If not, how is it made?

2. When the ear is sliced off the mouse to sew onto the person, does the mouse survive?