Most parents in the U.S. provide some sort of financial support to their adult children, multiple surveys have found. But often, financial aid goes the other way.

A 2015 survey by TD Ameritrade found 13% of American adults provided financial support to a parent. Millennials were far more likely than older generations to report they were helping their folks. Of people born between 1981 and 1996, 19% helped support their parents, compared with 13% of Gen Xers (1965 to 1980) and 8% of baby boomers (1946 to 1964).

Sometimes the money is provided happily, or at least without resentment, by those following cultural norms or personal conviction that they owe it to their parents. Other times, financial aid to parents is a source of tension — between parent and adult child, among siblings and between partners.

In my latest for the Associated Press, how to balance your finances while helping your parents.