Should you be an MD or a PhD if you want to do biomedical research?

This is excerpted from a talk that I gave a few years ago before students at the National Institute of Molecular Biology and Biotechnology (NIMBB) in UP Diliman. Many NIMBB students go on to pursue graduate training and a significant number become MDs, or PhDs. In my talk, I discuss what it takes to be an MD, using information from several MDs I have known in my life, and what it takes to be a PhD, from personal experience and those of several PhD friends.

There obviously is a big difference in the training that one has to go through to earn an MD, compared to that which one has to go through to earn a PhD (in a field that prepares one for a career in biomedical research). Both cases require sufficient knowledge of the basic sciences (biology, chemistry, physics and, of course, mathematics). This basic knowledge is gained during undergraduate training. 

In medical school, one learns all aspects of human biology in great detail. This is done mostly in the first two years. The next two years are mainly devoted to training in the practice of medicine. This training continues during a year of internship, followed by residency which involves specialization in a chosen field of medicine, e.g., pediatrics, surgery, internal medicine, etc. The period of residency depends on the field of specialization. One could undergo further training in a sub-specialty, e.g., allergy/immunology, nephrology, thoracic surgery, etc. The MD is awarded after the four years of medical training (in the US), or after the internship, i.e., after five years (in the Philippines).

To earn a PhD, one usually takes advanced courses in the chosen field of specialization and in related fields (to broaden knowledge). One then takes a candidacy exam, which is used to find out if the student has gained sufficient knowledge to start doing thesis research. In some places, the candidate is required to present a thesis proposal. After passing those hurdles, the student starts thesis research. The thesis has to be original, i.e., it has not been done before, and must make a significant contribution to existing knowledge. After completing the research, the candidate writes the thesis (essentially, writes a book about the research) and defends it before a panel of judges. If the judges decide that the thesis is significant enough and that the candidate had done enough, then the candidate is granted the PhD.

There clearly are differences between an MD and a PhD, both in training and in the knowledge and experience gained. Someone who has a PhD has done research on an original and significant topic. And the candidate has to have done it himself and by himself (for simplicity, I am using only male references). In contrast, someone who has an MD may or may not have done any research at all. Another difference is the number of years needed to earn the degree. The MD is usually earned after four (or five) years (unless the student is held back for some reason or other). In marked contrast, the number of years needed to earn a PhD depends on how good the candidate is in doing research, on how difficult the chosen thesis topic is, on the availability of needed tools and material, etc. — and on luck. Usually, the PhD is earned after five to seven years of graduate work (in the US). Some earn their PhDs in less time (in just two years in two cases I know of); some take much longer to earn their PhDs (more than 10 years in some cases).

PhDs and MDs, who want to engage in research, often continue their training by doing postdoctoral work. In the end, there will be little difference between those PhDs and MDs in their ability to do research. (Of course, an MD who tires of research can always go back to being a physician. No such recourse is available to a PhD.)

In my talk, I used two examples to emphasize the point.

The first example is a list of individuals who had major roles in the early development of molecular immunology.  They are: Rodney Porter, PhD (Nobel Prize, Medicine or Physiology, 1972); Gerald Edelman, MD/PhD (Nobel Prize, Medicine or Physiology, 1972); Georges Koehler, PhD (Nobel Prize, Medicine or Physiology, 1984); Cesar Milstein, PhD (Nobel Prize, Medicine or Physiology, 1984); Niels Jerne, MD (Nobel Prize, Medicine or Physiology, 1984); Michael Potter, MD (Lasker Award, 1984); Susumu Tonegawa, PhD (Nobel Prize, Medicine or Physiology, 1987); Philip Leder, MD (Lasker Award, 1987); Leroy Hood, MD/PhD (Lasker Award, 1987); Elvin Kabat, PhD (Medal of Science, 1991). As one can see, both MDs and PhDs have contributed to the endeavor.

The second example is the award in the year 2003 of the Nobel Prize for Chemistry to Peter Agre, MD, and Roderick MacKinnon, MD, while the Nobel Prize for Medicine or Physiology was awarded to Paul Lauterbur, PhD (Chemistry), and Peter Mansfield, PhD (Physics). Baligtad!

So, clearly, it doesn’t matter if you are an MD or a PhD if you want to do significant biomedical research. 

How about being both?

I have several friends who are both MD and PhD. One first became an MD, didn’t bother to do an internship, and then got his PhD in chemical physics. I could talk to him about anything. Another took his MD and PhD (in physical chemistry) at the same time (he also took every physics course his school offered), and became a full-fledged pediatrician. One could talk to him also about anything.  Another friend also did a simultaneous MD and PhD (in immunology), and also became a full-fledged pediatrician; and I had asked him about the medical implications of things I was doing (even those outside his field). 

There are definite advantages to knowing many things. So, if you can, become both an MD and a PhD. If you cannot, it would be good to have an MD friend if you are a PhD, or a PhD friend if you are an MD — someone you can ask for information or better yet, collaborate with.

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Eduardo A. Padlan was a research physicist at the US National Institutes of Health until his retirement in 2000. He is currently serving as an adjunct professor in the Marine Science Institute, University of the Philippines Diliman, and is a corresponding member of the NAST. He may be contacted at [email protected].