And yet, even with this help, the average student with loans at a four-year college graduates with about $26,000 in student-loan debt. Millennials who are lucky enough to have some, or all, of a college tuition’s burden reduced by their parents have a leg up on peers who are saddled with student debt, and they’ll be able to more quickly move out on their own, and maybe even buy their own house.

And that matters a lot in the long run: While many remain skeptical about the real-estate market, homeownership is still the primary way that Americans build wealth. But first-time buyers—a group generally made up of younger adults—have been scarce since the recession. And research indicates it’s not because many of them want to remain renters, but because they just simply can’t save up enough for a down payment, especially not the down payments needed in the expensive urban markets where so many Millennials prefer to live. According to Svenja Gudell, the senior director of economic research at Zillow, “There’s a ton of people out there who want to buy. In our most recent survey in the beginning of the year, we had 5.3 million renters interested in buying over the next year.”

But, because of their student-debt loads, they cannot. “When it comes to taking out a mortgage, they aren’t able to carry that mortgage payment because they have very chunky payments to make to the lenders of their student loans. So that’s certainly holding Millennials back along the way,” Gudell says.

A recent study by the real-estate company Trulia laid it out this way: Imagine an individual who earns $50,000 and is shopping for a $200,000 home (the median U.S. income and house price). This person would like to put 20 percent down. If he or she follows the popular financial advice to save 10 percent of his or her annual pay, it’ll take him or her about eight years to have that down payment ready to go. If that same person has $26,000 of student debt, which means monthly payments of $280 based on a 10-year repayment plan, it’ll take this person closer to nine years.

But even these numbers are optimistic, with many Millennials owing monthly payments much more than $280 per month, and making much less than $50,000 a year. And in many markets, a $200,000 house is hard to come by. In some of the priciest areas, such as San Francisco, it would take those with a college degree and student loans nearly 30 years to save up enough for a 20 percent down payment. For those without the wage boost that a degree brings, it probably won’t be possible at all.

According to Zillow, 43 percent of Millennials who got help from their parents in paying for school were also able to become homeowners. According to Census data the homeownership rate for all young adults was about 36 percent in 2014.