Researchers at Harvard have found a new reason for women to stop paying so much attention to pesky things like grades, and this time it isn’t even to impress boys or become a better contestant on The Bachelor. In today’s sexist news, women are dropping out of hard college majors like math and science because they’re self-deprecating perfectionists.  A new study examining why women still aren’t well represented in fields like science and math has concluded that they try too hard to be perfect, and drop out of their courses for fear of getting B grades. Women who receive a B in introductory STEM courses, like economics or engineering, are far more likely than men to drop those courses and spend their college career researching the elusive MRS degree.

Catherine Golden, an economics professor at Harvard, uses her incredible education to deduce that “women just don’t want to get things wrong… they want something where the professor will pat them on the back and say, ‘You’re doing so well!’” I can’t help but be a little disgusted that a female researcher reduces her findings to something so infantilizing. She goes on to explain that men have their “eyes on the prize,” but women can’t handle a little negative feedback.

Of all the reasons women abandon STEM fields, this one seems the least likely. When I lament my lost career as a neuroscientist, I blame things like a lack of engineering toys marketed toward girls, or the fact that I never had a female math teacher, or my conviction that high school boys didn’t like smart chicks (and a love of French novels, but that’s not the point).

But no, it’s not that internalized sexism and lack of mentors. It’s that our standards are just too high to carry on in math and science.

It’s really no surprise that women who receive a B in science or math take that as discouragement, but I can’t chalk this up to “B-phobia.” If women abandon degrees because they’re not acing those exams, perhaps it’s because women and minorities typically have to work twice as hard to get the same professional respect as a man gunning for the same job. It’s possible that female students decide they’re not cut out for STEM degrees after one less than perfect grade. But if they lose faith in their abilities so quickly, it’s likely that the B is just the final straw after years of being told they’re pretty but not smart, and that ditzy girls end up happier.

More women should absolutely pursue degrees in STEM fields, and Professor Goldin is correct that women should be confident enough to stick to their dreams through a rough semester. The more women we put in highly visible, prestigious fields, the more likely we are to shrink the wage gap and get basic professional benefits like paid maternity leave. But telling them to pay less attention to grades is the wrong answer. As long as we’re outnumbered and expected to sit on the sidelines, women should tackle tough majors with every ounce of perfectionism they’ve got.