A new study shows that the parents who take on the greatest college debt repayments tend to be those who are black, have two children 17 or older with college-related debt, have a college degree themselves and upper-middle income or high income earners. The average debt was around $21,000. High-income parents repay an estimated $30,000 in college debt on their child’s behalf.

“This could have implications for parents, such as delaying retirement,” said study co-author Jennifer Ailshire, an assistant professor at the USC Leonard Davis School of Gerontology and the USC Dornsife College of Letters, Arts and Sciences.