For all of the conversation the past week about Mitt Romney's views on federal income taxes and personal responsibility, his insistence that "I have inherited nothing" may be the most thought-provoking.

His comment, which was among those he made in the video of a fundraiser that Mother Jones magazine posted Monday, has inspired a few skeptical reactions, given his privileged background. But leaving the breadth of his advantages aside, the comment speaks to an often unspoken distinction among families that can determine who gets ahead, who gets along and who merely scrapes by.

Some parents help their adult children financially, while others cannot or do not. This living inheritance comes in many forms. It exists along a range from the free room and board for a 23-year-old intern to a stay of years for a 43-year-old single parent who has lost a job or recently divorced. The contribution can be as small as a first month's rent or as large as the 25 years of payments that many parents now make on college loans they took out so their children would not have to.

The less help you have as an adult starting out, the harder you have to work to make the next geographic, career and economic step up. If you lack that help, any and all mistakes (and there will be plenty) often have much bigger consequences. And the lack of any family help can have a compounding effect on the millions of people who have negative net worths well into adulthood, thanks to their student loan debt.

To parents like Kevin O'Brien, a 70-year-old retiree who divides his time between Park City, Utah, and Naples, Fla., this is simply the new order of things, something that needs to be part of a financial plan.

He methodically checked off the help he has provided his three children during divorce or job loss and transition and the assistance his sisters and close friends have provided their children.

"We see it again and again," he said. "Most people don't like to talk about it, but the people you spend a lot of time with, the stories come out over lunch or a drink."

This has required a bit of sacrifice from O'Brien, a retired physicist, and his wife, a retired pediatrician, but not so much that they don't do it willingly.

"When they get in trouble, I don't want them to go so far downhill that they'll never get out," he said. "As a parent and grandparent, I think it's a fundamental responsibility for me, and one I'm gladly willing to fulfill."

To Karen Kline in Orinda, Calif., the idea of her lawyer son and graphic designer daughter not having health insurance was "unacceptable." So she paid for it until they qualified for the benefit at their jobs. Kline, now 63, has savings and will retire in two months with a pension, so she was able to afford the help.

Then there are the scores of young adults taking up temporary residence in their childhood bedrooms. Author Sally Koslow refers to a bed and cable access as "the middle-class trust fund" in her recently published book "Slouching Toward Adulthood."

These parents do not deliver the usual platitudes about the next generation doing better than the last. They are merely trying to guard against downward mobility, a natural instinct.

But many young adults don't have families that can cushion their entry into adulthood. Jenna Leigh Wilson has just over $100,000 of student loan debt after earning degrees from Villanova and the University of Pennsylvania. Her mother died three years ago of breast cancer, she still has three siblings in college or younger, and her father is not in a position to help.