Newsweek mulls whether the three women now on the U.S. Supreme Court will somehow transform it. Social scientists contend that the difference is more than just cosmetic. They cite a 2006 study by the Wellesley Centers for Women that found three to be the magic number when it came to the impact of women on corporate boards: after the third woman is seated, boards reach a tipping point at which the group as a whole begins to function differently.
According to Sumru Erkut, one of the authors of that study, the small group as a whole becomes more collaborative, and more open to different perspectives. That’s because once a critical mass of three women is achieved on a board, it's more likely that all the women will be heard. In other words, it's not that they bring any kind of unitary women's perspective to the board–there's precious little evidence that women think differently from men about business or law–but that if you seat enough women, the question of whether women deserve the seat finally goes away. Women speak openly when they don't feel their own voice is meant to reflect all women.