Rabbi Hershel Schachter (Rosh HaYeshiva of RIETS) says:
"There is a terrible misconception that the laws of Shabbos do not apply to doctors. This is absolutely incorrect. No profession exempts anyone from any mitzvos. Medical students are certainly not exempt from Shabbos observance. And even after having completed his school years, the future doctor must take special care to make sure he has a Sabbath-observant residency. If this can not be arranged, the student must simply look for a different profession."
That's a pretty strong statement there. And since there are some fields of medicine that don't really offer such residencies, is R' Schachter saying that an Orthodox Jew cannot realistically become, say, a surgeon or a cardiologist? (Though if anyone does know of a shomer-shabbos surgical residency, I'd be interested to hear about it.)
Clearly, though, there are plenty of observant doctors today who did go through residencies that were not particularly Shabbos friendly - so what gives? Are all these people in error?
Compare the above with the responsum of Rabbi Dr. Mordechai Halpern of Shaare Zedek:
Question: I am a medical student in the United States and am in the process of choosing a residency. Here in the States, there are some specialties in which one can obtain a residency that does not require working on Shabbos (eg, internal medicine, pediatrics, psychiatry and radiology), whereas there are other specialties where working on Shabbos is a requirement (eg, general surgery, OB/Gyn, urology, cardiology). Is it permissible to pursue training in one of these latter fields in the United States?
Answer: It is preferable to train in a Shomer-Shabbat program. If one feels very strongly that he can best serve as a physician in a field which has no such program, it is permissible to train in a regular program. However, one should be very knowledgeable concerning the laws of Shabbat, which is quite a complicated matter.
Looks like Rabbi Dr. Halpern takes a much more reasonable approach. It seems obvious to me, however, that Halachic conflicts are almost inevitable when working in any field on Shabbos but that shouldn't be reason enough to make people turn their back on what otherwise could be their calling, especially when the unimpeachable goal is to save human life and/or to better the quality of life for those who are suffering. As the famous saying goes, I'm not maikil on hilchot Shabbos, I'm machmir on hilchot pikuach nefesh!
I never liked the idea that Halacha is a barrier to the success of man. What it is (or should be), is taking a different approach through life that allows you to get to the same destination - but as a Jew.