Questionnaires were distributed to 346 fourth-year students in nine medical schools. The students were asked to state their selected specialty and to rank the importance that each of 25 influences, listed as questionnaire items, had had in making their choice of specialty. Factor analysis showed that particular items were significantly associated with particular factors. The first factor emphasized perceived lifestyle (items in this category gave importance to remuneration, personal time, and prestige); the second factor emphasized cerebral activities and a practice orientation; and the third factor stressed altruistic values and attitudes. The authors classified the selected specialties into three groups: those characterized as having a non-controllable lifestyle (NCL), those with a controllable lifestyle (CL), and surgery. (CL specialties were defined as those that allow the physician to control the number of hours devoted to practicing the specialty.) Data were analyzed using factor analysis, and analysis of variance, and the Scheffé method. Analysis indicated that the perceived lifestyle factor was most closely associated with the responses of those students choosing CL specialties. Furthermore, this factor received the highest total loading of the three factors from all the students, thus indicating the level of interest in lifestyle factors. Responses to items that defined the cerebral and practice factor were highest from the group of students choosing CL specialties and lowest from the group choosing NCL specialties. The NCL students scored highest in the altruism factor and the CL students scored the lowest. The surgery and NCL groups were similar in attitude patterns, and both were substantially different in attitude patterns from those of the CL groups.(ABSTRACT TRUNCATED AT 250 WORDS)