Note that women make up a majority of those who earn bachelor’s degrees in biology these days. If a college considers gender ratios in (intended) majors as an admission factor, then a female applicant indicating biology is unlikely to gain any advantage.
Among STEM majors, it is mainly CS and engineering majors where women tend to be the least represented. Math and physics show female underrepresentation to a lesser degree. At the other end, health professions (e.g. nursing), education, and psychology have female overrepresentation.