(Amy Cavenaile/The Washington Post; iStock)

For many would-be home buyers, the biggest obstacle isn't the income to cover the mortgage or the credit score to qualify for one. It's the huge pile of cash you have to hand over on closing day. A first home — especially in a high-cost city — demands not just that you make enough to cover the payments, but also that you have a lot to start with.

And that's where it comes in really handy to have parents with money.

Adult children who get financial help from their parents — whether that money is intended for housing or not — are significantly more likely to become homeowners. This finding, from a new working paper by Dowell Myers, Gary Painter and Julie Zissimopoulos at the University of Southern California, illustrates how housing itself functions as a tool of wealth transfer. At least for those who can tap into what Myers calls "the Bank of Mom and Dad."

"Minority parents have like a fifth of the wealth of white parents," he says. "If that’s the bank, then the bank is not going to be performing equally."

The adult children of parents in the top quartile of the wealth distribution are about eight times as likely as children from the bottom quartile to receive sizable financial help, defined here as at least $5,000 over a two-year period in data from the Health and Retirement Study longitudinal survey. White children are more than three times as likely as black children.

Myers and his coauthors wanted to know how that money affects an adult child's chances of becoming a homeowner. They looked at adults ages 20 to 49 who were renters in one year of the study but had transitioned to homeownership by the next wave two years later. Adult children who received money from their parents during that window were 23 percent more likely to become a homeowner. When the researchers controlled for factors like parental wealth — the fact that rich parents are more likely to give in the first place — the probability still went up by about 13 percent.

Broken down by race, though, an odd pattern appeared. Money from mom and dad boosted a white child's chances of becoming a homeowner by about 3 percentage points. For a black child, financial help is actually associated with lower chances of becoming a homeowner:

Black children, in effect, are less likely to receive financial help in the first place. But even when they do, it doesn't boost their odds of buying a home the same way it does for whites and Hispanics. And this remains true even even when the researchers adjust for differences in parental wealth.

Part of what's happening may be that parental help to adult black children goes to causes other than homeownership, like education or child care, or even rent. This survey data covers financial help of all kinds. But the researchers also chose not to focus solely on money meant for homebuying because any aid can have the same effect: An adult child who gets help with student loans, for instance, would have more money left over for a down payment on a house.

"There’s a racial disparity that persists despite all controls, and that’s always discouraging when you find that," Myers says. "There’s still something there. They’re not having the same likelihood of homebuying. Or they don’t have equal access to homebuying, or maybe they don’t have equal preference for homebuying. We don’t know."

This data likely underestimates the share of children who get help, and the effect of that help on their homebuying. It covers only gifts from parents to their children. But a married couple buying a home may get help from two sets of parents.

The larger pattern points to how historic disparities in the housing market are transmitted over time, from parent to child to grandchild. Earlier generations of blacks were excluded from homeownership by lending practices and government policies, and as a result those generations didn't accumulate the housing wealth that enabled them to pass money onto their children.

"Now how do you get other people started, so they can do that for their kids?" Myers asks. "We haven’t got that formula figured out at all. I don’t think we’ve figured out how important it is that we want other people's kids to be successful."

If anything, these racial disparities have only widened since the housing bubble, which had a much more devastating effect on the wealth of black and minority families.

Retiring baby boomers, Myers adds, should be particularly interested in this problem. More of them will soon want to sell their homes as they downsize or move in with their own children. But as demographics shift and the United States becomes an increasingly diverse country, minorities with less access to homeownership will make up a larger and larger share of the pool of potential home buyers. And so who will buy the baby boomers' homes if we don't change these patterns?

"The housing market is more and more dependent on people of color," Myers says. "So it’s more and more important that we figure out what’s preventing them from fully participating in it."