lol i'm guessing he thinks biology is a soft science. i'd love to hear his explanation as to why. also, you can be an emotional mess but be good at technical scientific topics. sometimes working with a field that deals with facts and objects is better for emotional people, since the solution to problems doesn't require a certain emotional state from you. you can be happy or miserable and a theorem still works out the same way. jobs like a therapist or caretaker or a social worker on the other hand, require you to have a certain level of control of your emotions or you won't even be able to even stay employed.
no, the reason men gravitate to muh hard sciences and women to muh "soft" ones is just because more women tend to be interested in studying things like people and animals and the environment, and more men tend to be interested in studying faceless mechanisms and technology that they can tinker around with, like how boys will compulsively take apart a mechanical pencil and try to put it back together. it doesn't take a galaxy brain to do that, girls just don't care as much. area of interest is not a marker of intelligence, it's the way you think and apply your area of interest.