Much has been made of the fact that Elena Kagan’s confirmation last month means that for the first time in American history, there will be three women on the high court. But beyond a sense that the court will be slightly more representative of the American people, and the possibility of yet more intriguing white lacy scarves from on high, what does the difference between having one, two, or three women at the court really signify?

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 having 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. In no small part, she writes, that’s because once a critical mass of three women is achieved on a board, it’s more likely that all of the women will be heard. In other words, it’s not that females bring any kind of unitary women’s perspective to the board—there’s precious little evidence that women think fundamentally 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. And women claim they are finally able to speak openly when they don’t feel their own voice is meant to be the voice of all women.

Nobody has been a stronger advocate for the need to reach a critical mass of females on the court than Justice Ruth Bader Ginsburg. While she is ordinarily quite reticent about all things soft and snuggly, she has been ever more vocal about what women bring to the court. As she explained to Mark Sherman of the Associated Press in early August, at least once every term for the 13 years that she and Justice Sandra Day O’Connor shared the bench, someone arguing a case would mistake her for O’Connor or vice versa. Last term, nobody mistook her for Sonia Sotomayor, however, and she contends that the days in which the first two women were fungible “curiosities” are finally over.

Ginsburg knows better than anyone that she and O’Connor had nothing like a singular worldview. But what they had—what the court lacked—was a perspective about half the population. We may not think that matters—and we may wish it didn’t change things—but in some cases, it matters a lot. Ginsburg told the AP about a 2009 case involving a 13-year-old girl who was strip-searched by school officials looking for ibuprofen and the ways in which—at oral argument—some of her male colleagues compared that strip-search to the locker-room high jinks of teenage boys. A court that appeared very sympathetic toward the school district after oral argument ended up voting 8-1 that the search was unconstitutional. (Clarence Thomas disagreed.) Nobody credits the Constitution with changing in those short weeks. What changed was that Ginsburg spoke out, both from the bench as the case was being argued and then again in the media while the case was still pending, explaining to USA Today’s Joan Biskupic that her colleagues “have never been a 13-year-old girl” and adding that with respect to that strip search, “I didn’t think that my colleagues, some of them, quite understood.” It was as close as most court watchers have ever come to hearing Ginsburg speak fighting words.

Justice Ginsburg wasn’t trying to embarrass her colleagues by imposing a politically correct litmus test on them. I think she was merely trying to point out that she might have had something to teach them about young girls. The personal understanding she has brought to the case of teenager who was strip-searched is as critical to the court’s deliberative work as Justice Samuel Alito’s personal concern for students subject to religious discrimination or Justice Clarence Thomas’ special solicitude for the students who benefit from affirmative action. You can dismiss each justice’s special sensitivities as bias, I suppose, or you can celebrate the fact that judges have a lot to teach one another about how different lives are experienced. Some interesting empirical studies show that male judges may change their views on some gender-related issues when they sit on a panel with a female judge. Perhaps you just don’t know what you don’t know about women until someone is there to explain it.

For centuries, the Supreme Court has been zealously opining on whether or not women are fit to practice law, or tend bar, work a 10-hour day, support their families, use birth control, or terminate their pregnancies. For most of that time, women influenced that debate only if they were lucky enough to be married to a justice. The presence, for the first time, of three women on the Supreme Court may not reshape constitutional law in any profound way. It may not even change the court all that much. But as the justices continue to decide the cases that affect the ways in which women in America are educated, hired, compensated, and afforded control over their bodies, it can only be a good thing to have three voices at the table with actual experience in the field.

A version of this article appears in this week’s Newsweek.

Like Slate on Facebook. Follow us on Twitter.