Demand for housing from millennials appears lower than what many experts predicted for this year, and housing leaders are trying to figure out why.

Certainly interest rates have risen over the past year, but they remain at historical lows. Home prices also rose substantially, yet affordability remains high in many markets.

“There is something else more mysterious going on, and I think generational changes are most likely the culprit,” said Michael Orr, director of the Center for Real Estate Theory and Practice at the W.P. Carey School of Business at Arizona State University. “It is just very difficult to prove it scientifically.”

But talk to people in the millennial age group and you quickly learn that people in their 20s and early 30s witnessed the housing crash and, unlike older generations, tend to view housing as a risky investment.

Older generations, meanwhile, remain confident that housing is a good investment, Orr said.

“Their faith hasn’t been shaken by the past few years because they’ve been around long enough to know that over the long term, owning a home has generally increased your wealth,” he said.

Millennials who graduated from college recently may not be in the ideal job due to the nation’s stagnant economy, so they are less likely to want to put down roots. They fear getting locked into a mortgage and potentially stuck in a particular labor market.

“Renting, they say, has maximum flexibility,” Orr said. “If a job comes up in another city, they can leave their rental and go. If they own a home, they — quite rightly — think it will take longer to make the move.”

Student loan debt continues to cripple the millennial first-time homebuyer segment.  According to research by the Federal Reserve Bank of New York, fewer 30-year-olds in general have bought homes since 2008, but the hardest hit segment of this new homebuying population is the group with student loan debt. In 2013, the average total debt for student borrowers was nearly $30,000. This amount of debt, and the monthly obligation to repay the student debt, drastically hinders these potential homebuyers’ opportunity to meet the ability-to-repay requirements in today’s mortgage industry. Millennials also are getting married less and having children later in life, leading to less demand for single-family homes. While having children has sparked several friends to buy homes, Scott Smith, 26, of Dallas, doesn’t have children and doesn’t see the need for a house at this point in his life, although it is a future goal for him and his wife, Elise.

While homes for sale often are in the suburbs, many millennials prefer a more urban lifestyle.

Wells Fargo, in a March 2014 commentary by senior economists Mark Vitner and Anika Khan, said future housing cycles likely will include more apartments and townhomes.

“The housing recovery has been stronger in markets where the employment conditions have been more buoyant, such as Seattle, San Jose, Austin, Orlando and Nashville. These are some of the markets favored by millennials,” the report said. More apartments and townhomes in future housing cycles reflects “changing demographics and the increased preference by younger households for urban lifestyles,” the report said.

Towns with lively downtowns appeal to millennials, who are known for spending time eating out in restaurants and who favor public transit. They might be open to buying condos, if ones within their price range were available, but many of the condos being built in major metros are of the luxury variety and out of financial reach for many millennials.

In many instances, buying a home simply isn’t a top priority at this point in their lives, although it still remains a long-term goal.

“They’ve got far more pressing things on their mind than owning a home,” Orr said. “They are saying, ‘Well, maybe when I’m 35 I’ll look into it.”