Shinya Yamanaka: I was an orthopedic surgeon, and my first failure was that I was not good at doing surgery, and that failure gave me an opportunity to move to basic science.  Then my first major was pharmacology, and in pharmacology we only use many inhibitors and stimulators, all just drugs. And any drug cannot be 100 percent specific and 100 percent effective.  So although I did many, many experiments, I did not obtain the answer, because  the drugs I used weren’t specific enough. So that was kind of my second failure in my career.  But that second failure got me interested in knockout mice, mouse technology. So I think failure is important in my career.