The chief internal barrier to success and persistence in STEM is students; underestimation of their own abilities (self efficacy). Mentors can help by affecting young women’s sense that they can “do science.”
RISE: Research Internship in Science and Engineering, Undergraduate females

The assertive behavior needed to successfully negotiate a research placement at a competitive institution is considered rude and even foreign to rural values, especially for women
Wiser Lab Research for First Year Undergraduate Students

First-year college students often believe that introductory science classes are designed to eliminate students not good enough to do science
WISE Beginnings, first year undergraduate females

Some Faculty also believes that students leave science early because they lack certain attributes of ability or character, and that their leaving is a part of the natural weeding-out process.
WISE Beginnings, first year undergraduate females

A young woman talented in STEM typically enters college with higher grades that a similarly gifted young man but may be less well prepared, her course work having been less rigorous. She has high aspirations but her self-esteem has been declining since early adolescence and it is at its lowest point ever. Having lost confidence in her own opinions, she tend to agree with others so she will be accepted and is unlikely to assert herself in class, and does not stand up well to criticism. A C on her first math or science test may lead her to change majors because she thinks she is not good enough. On vocational personality tests, she tends to score higher than average on scales for both investigative and conforming.
GEOS: Encouraging Talented at-risk youth women, undergraduate

Girls routinely underestimate their ability in such subjects as math and physics, subjects traditionally viewed as men’s turf.
WISE women at Stony Brook, undergraduate

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