At Brown, Amherst, and Swarthmore, the male admission rate was three percentage points higher than that for females; at Wesleyan and Tufts, the margin was 5 percentage points.

That might not sound like a lot. But in these hypercompetitive times, when some schools receive 30,000 applications for a few thousand slots, a small gender gap can make a world of difference. “If there was a tie between two equally qualified candidates of different sexes,” Kenyon’s admissions director admitted a few years ago, “the male would be more likely to get the admit letter, and the girl would get wait-listed.”

The reason she gave was simple: If Kenyon took in too many women, it would become unattractive to female and male applicants alike. That’s been the mantra of other admissions officers, too, who warn about a “tipping point” of 60 percent. Once a college goes over that, in its fraction of females, fewer people want to go there.

But I’ve never seen any compelling data showing that’s true. And even if it is, the rationale sounds suspiciously like the one used to limit the number of Jews at selective colleges a century ago. “The summer hotel that is ruined by admitting Jews meets its fate because they drive away the Gentiles,” Harvard President A. Lawrence Lowell warned in 1922, “and then after the Gentiles have left, they leave also.”

Today, we’d never countenance a university leader who argued against admitting too many members of a given ethnic or racial group, lest the school become less attractive to others. Studies have shown that some institutions have set higher standards for Asian-Americans, who need SAT scores about 140 points higher than those of white students – when all else is equal – to have the same chance of getting into an elite college. But I haven’t heard anyone warn that Asian-Americans will repel other applicants if they fill too many slots at an elite college.

Instead, the rationale there – as with affirmative action – is to provide more opportunity for underrepresented groups, especially those who have historically suffered from discrimination.

Plainly, men aren’t in that category: The last time I checked, they held most of the important positions of power and influence in American society. And yet, college admissions offices lower the standard for young men – effectively raising it for women – simply to make sure that the men keep coming. The boys won’t like it if there are too many girls. And eventually, the theory goes, the girls won’t like it either.

But what does that do to the self-image of our young women? Although girls outperform boys in nearly every academic category, they also report less confidence about their scholastic abilities. Surely part of the reason is the college admission system, which routinely rejects talented girls in favor of less qualified boys.