“It makes you feel like a failure as a parent, to be unable to help your children and to have all your hard work end in a pile of debt,” said one New Jersey man, who took out a second mortgage of $280,000 to help cover his children’s college costs. “I sent my older kids to private colleges, and I was happy to do it because it’s how you help them get started off. But I can’t do it for the youngest, and I haven’t even been able to start the conversation with him.”

Ms. Fitzgerald said she had little hope of a comfortable old age. She has no health insurance. She knows that the odds of finding a good job in her 60s, with no college degree, are slim — and she knows that the government will take part of her Social Security, in payment of her debt, which she said had now ballooned to about $40,000 because of penalties for nonpayment. At one point, she said, the Internal Revenue Service seized a $2.43 tax refund.

Jenni has volunteered to take on her mother’s debt, but Ms. Fitzgerald has refused, saying it is her legal and moral obligation, and anyway, Jenni has her own loans to pay off — about $220 a month — and not much discretionary income. The very suggestion that Jenni might take on her debt annoys her.

“Don’t you think she is doing enough for me now by supporting me a hundred percent, financially, by my living with her and her extending her resources?” Ms. Fitzgerald asked. “The whole idea was for her to get a college education so she can succeed in life; it is hard enough just to do that without being burdened with her mother’s welfare, like I was her child.”

Jenni occasionally jumped in with explanations or clarifications, as she and her mother sat in the living room discussing their situation. When Ms. Fitzgerald talked of being depressed last year, so overwhelmed by the cartons of documents and dunning letters that she threw them all out, Jenni said gently, in an almost maternal tone, “But you’re doing much better now.”

Many young people live with deep guilt that their education has pushed their parents into debt, and perhaps ruined their credit rating. Even those who do not know exactly how much money their parents have, or how much they owe, worry about how their debt will affect their parents’ lives.