Parents take out second mortgages and deplete their savings to send their kids to college. But could they actually be hurting their kids? New research says college students who get more financial help from their parents get lower grades.

Laura Hamilton published the research this month in the American Sociological Review. She’s an assistant professor of sociology at the University of California, Merced. Students who get more help from their parents aren’t necessarily rich, Hamilton says. Many parents take out loans to help their kids pay for college. But she says students who don’t have to worry about money may be less invested in college. They can also take more advantage of the college social scene.

“It takes a lot of money to eat out, to party,” she says. “If you have a job in the evening, you can’t be partying that night.”

So should parents let their kids go it alone? At today’s prices, that’s unreasonable, says Lynn O’Shaughnessy, who writes “The College Solution” blog. It is reasonable to make them pay for textbooks or nights out, she says and to set some standards.

“Convey to them they have to be responsible, and if they don’t keep up with their grades, there’s going to be some consequences,” O’Shaughnessy says.

Another reason to help out: Kids who get financial support from their parents are more likely to graduate on time.