In the past, medical schools and most dental and veterinary schools have had a relatively simple set of required courses, which included: 2 semesters each of Inorganic Chemistry, Organic Chemistry, Biology and Physics (each with corresponding labs), and English. A few schools also required or recommended Biochemistry, Math and/or Statistics, or additional Biology courses. You will still see these requirements on many websites and in publications.
When the Medical College Admission Test (MCAT) was revised in April 2015, students also needed, in addition to the above courses, a background in Biochemistry, Statistics, Psychology and Sociology. Some medical schools began to require these courses; others added them but required fewer Chemistry or Physics classes. And some transitioned to "competency-based admissions", which means that applicants were expected to demonstrate competency rather than just completing a list of required courses. The intent was to allow applicants more flexibility and diversity in choosing courses and preparing for medicine.
This is a period of change. Not all medical schools have transitioned to competency-based admission and will still expect applicants to have the traditional semesters of Chemistry, Biology, and Physics as a foundation. And even medical schools that now require "competency" will still expect applicants to have taken coursework in these areas. Since Duke students generally apply to more than 20 medical schools, you will need to meet the course prerequisites for all the schools to which you want to apply. Our advice is to complete a fundamental set of courses in Biology, Chemistry, Physics, Math, Statistics, Biochemistry, Psychology and Sociology. Then periodically check the requirements of medical schools in your home state and any other schools you are interested, to see their requirements, expectations and policies.
Toward this goal, we have a set of prehealth courses at Duke that we recommend, and which will address most requirements for medical, dental, and veterinary medicine schools. See the topics in the left margin.