as in, M.S. and J.D.
but really, it depends on what you want to do. I started off in science, planning to go into academia, and then realized that was not a good way to effect change. scientists shy away from being involved in social/political issues, and the ones who don't tend to lose credibility amongst their peers. thus, I am going from a Master's to a J.D instead of a Master's to PhD. but like I said, it really depends on what you want to do. I strongly recommend talking to a lot of people in both fields.