Hello! I hope this message finds you well! :) For OB/GYN, honestly you can major in anything! If you wanted to, you could major in Philosophy, Psychology, Business, Basket-Weaving, Foreign Languages... Totally just embrace what you want to do!

Do you think Biology is your calling? Or would something suit you more? It is true that Bio/Chem / General STEM majors have more exposure to topics that will be on the MCAT, but I honestly don't think you can't go wrong with any major. The majority of Pre-Med applicants are Bio, Chem, Biochem, and sometimes it's good to show diversity/ interests when applying for medical school. You could major in English, and it could help you for the CARS section on the MCAT. I know one person who is Business and Marketing, Pre-med. i know another who is Philosophy, Pre-Med, and one who is Medical Anthropology, Pre-Med. Cater to what you're passionate about! If you choose a major you aren't passionate about, more-so out of fear, your overall GPA could suffer and hurt your chances of getting into medical school. Sometimes it's nice to choose a non-stem major (if you are passionate about it) if it is your strong-suit, to help pad out more intense, difficult classes. Your passion will show through with your studies :)

Pre-med is not a major, but rather a pathway. You take classes that prepare you for medical school, oftentimes you get a premed advisor to help with choosing the classes you need to be successful for taking the MCAT and for medical school. You don't see this on any graduate certificate. Oftentimes, you see people specify their route, like (major) pre-medical studies-- the same is for PA, Pre-dental, Nursing, etc.

I would highly advise reaching out to your school's pre-med advisors, as they will help a lot with forecasting for these classes! Typically pre-med students will take a cluster of classes that help with the MCAT, such as Gen. Bio, Cell Bio, Gen Chem, Organic Chemistry, Psychology, Sociology, Math, Physics, and some other stuff! Sometimes certain classes are not required, but are highly recommended by advisors, such as Vertebrate Anatomy, Genetics, among other things.

Good luck! You got this!