Mel Gibson introduces Dr. Neil Riordan to Joe Rogan to talk about stem-cell research. The different kinds of research available, the effects of it and the legal problems surrounding it.Mel Gibson introduces Dr. Neil Riordan to Joe Rogan to talk about stem-cell research. The different kinds of research available, the effects of it and the legal problems surrounding it.Mel Gibson introduces Dr. Neil Riordan to Joe Rogan to talk about stem-cell research. The different kinds of research available, the effects of it and the legal problems surrounding it.