We know that in 2001 it was believed 78 stem cell lines existed. But now we know there are only 22 that are viable, and they have been contaminated with mouse stem cells.
People tell me I look mournful. They say, 'Cheer up, Dan, it's not that bad!' Sometimes I just look into space, which freaks people out. If I was ever required to do anything other than look haunted, I could. I'm a happy person.