bias against women and the black to pursue advanced degrees?

顯然很多美國大學教授還是認為，女生和黑人不太具有讀博士班的天份 (但亞洲人沒有這個困擾)。 這是美國大學教授的偏見還是根深蒂固的文化使然？
http://www.economist.com/news/science-and-technology/21639439-women-are-scarce-some-not-all-academic-disciplines-new-work-suggests