BOSTON — Students and alumni at some of the nation’s top universities are urging their schools to reconsider admissions policies that give an edge to relatives of alumni.

Campus groups for first-generation and low-income students at 12 elite universities issued a joint letter today asking their schools to review the impact of so-called legacy admissions policies through proposed campus panels that would include students and alumni. The coalition also called on their schools to publicize policies and data on the topic.

“This campaign is not about whether or not legacy applicants like our future children deserve their place in their respective universities,” the group wrote. “It is about ensuring that all students have equal footing in the admissions process regardless of whether or not their parents attended a certain university.”

Officials from the 12 schools did not immediately comment on the letter.

Although most colleges closely guard the weight they give to legacy status, data released by some Ivy League universities show that relatives of alumni are admitted at far higher rates than the overall applicant pool.

The letter is signed by student groups at Harvard, Brown, Yale and all other Ivy League schools except Dartmouth College, which does not have a campus group for first-generation students, the coalition says.

Others in the group come from prestigious private schools including Amherst College and the University of Chicago.

While students in the coalition acknowledge the practice could benefit them — and some said they felt conflicted about challenging it — they argue that ending legacy preferences would give more low-income and first-generation students a shot at attending prestigious schools.

“No matter how hard you work, you can’t make yourself a legacy. No amount of SAT studying could make up for that,” said Alfredo Dominguez, a 20-year-old first-generation Columbia student and a member of the coalition. “They do actively try to admit students from diverse backgrounds, but this is another step or barrier to getting to a more equitable place.”

Students aren’t immediately asking schools to ban the practice but say they want to start a conversation. The group opposes legacy policies but recognizes it’s a complicated issue that deserves a thorough review, said Viet Nguyen, a Brown alumnus leading the effort.

The coalition is adding pressure to elite admissions offices at a time when they’re already under renewed scrutiny. Harvard, for example, is being investigated by the U.S. Justice Department over the role that race plays in admissions after a group of Asian-American students filed a discrimination lawsuit.

Past studies have found that most highly selective private universities give an advantage to legacy applicants, but most closely guard the policies and their impact.

Among the 12 schools targeted by the coalition, only Princeton University would provide The Associated Press its admission rates for legacy applicants. There, the rate for children of alumni has hovered around 30 percent for the past five years, compared with about 7 percent for all applicants.

Cornell University declined to provide acceptance rates but said 16 percent of this year’s freshmen have a parent or grandparent who attended. The share at the University of Pennsylvania is 14 percent.

Schools defend the practice by saying it encourages alumni to donate, which adds money for student scholarships. Many say it’s used only as a tiebreaker in close decisions.

But some critics say there’s evidence suggesting otherwise.

“It provides a substantial benefit to applicants,” said Richard Kahlenberg, a senior fellow at the Century Foundation, a New York-based think tank.

“At a time when we’re racking our brains about how to attack inequality, here’s a policy that is designed to provide a preference to some of society’s most advantaged students.”

Opponents cite research including a 2010 study at Harvard finding that at 30 elite schools, the probability of admission increased 45 percentage points for students with a parent who attended. Some other studies have found no connection between legacy policies and alumni fundraising.

Among the practice’s critics are some who have benefited from it. Former President George W. Bush, for example, called for an end to legacy preference even though it helped him get into Yale, which his father and grandfather attended. Instead, Bush said schools should judge applicants simply based on merit.

Students in the coalition say their next step is to organize votes at several schools to gauge support for the goals outlined in their letter. That’s planned at schools including Brown, Yale, Princeton and Cornell.