Recently on a podcast I heard the assertion (so I don't know of a study) that female students may be observed to do better on average in math classes than males

Recently on a podcast I heard the assertion (so I don't know of a study) that female students may be observed to do better on average in math classes than males, but males were disproportionately much more confident about their abilities than females. I have observed this difference myself anecdotally, it is sometimes almost comical in young males to have completely unearned confidence in math and technical skills. I have always thought this is tied to normal effects of testosterone.