The medical/surgical specialty of Obstetrics and Gynecology (OB/GYN) has undergone significant transformations over the last 40 years, particularly with regard to its gender composition, its generational cohorts, and its models of practice organization. All of these changes have had profound effects on its professional identity within and outside of medicine, as well as influencing the professional identity of individual OB/GYN physicians themselves. Little sociological research has paid attention to these changes in medicine; almost none has examined OB/GYN itself. This case study of OB/GYN, drawing from interviews with over 50 OB/GYN physicians spanning three generations and both genders, finds that looking at these transformations within OB/GYN illuminates changes in professional identity both within this specialty and in the larger profession of medicine. The historical schema of medical work-devotion, which demands that physicians prioritize their patients and profession above all other responsibilities, has diminishing influence within OB/GYN. By comparing the attitudes of physicians in Baby Boomer, Generation X, and Millennial cohorts and men and women toward this schema, it becomes clear that it is cohort replacement rather than feminization that is driving these changes in medical work-devotion and professional self-identity. The professional identity of OB/GYN as a whole has also changed radically over the last 40 years, as the field has shifted from being overwhelmingly male to being predominantly female among younger physicians. Examining gender in this high-status field upends expectations that occupational sex segregation always leads to sex stratification that disadvantages women, though men still experience areas of advantage in the field. Lastly, previous models of practice setting inadequately understand the true differences in the organization of medical work. Conceptualizing the practice of obstetrics as a coverage continuum—from physicians covering their own patients to shiftwork—makes the differences between practices much more clear. Placement on the coverage continuum drives differences in physician work-life balance, income models, work hours, physician-patient relationships, and the experience and satisfaction of physicians and patients.