As she nibbled on strawberry shortcake, Jessica LaShawn, a flight attendant from Chicago, tried not to get ahead of herself and imagine this first date turning into another and another, and maybe, at some point, a glimmering diamond ring and happily ever after.

She simply couldn't help it, though. After all, he was tall, from a religious family, raised by his grandparents just as she was, worked in finance and even had great teeth.

Her musings were suddenly interrupted when her date asked a decidedly unromantic question: "What's your credit score?"

"It was as if the music stopped," Ms. LaShawn, 31, said, recalling how the date this year went so wrong so quickly after she tried to answer his question honestly. "It was really awkward because he kept telling me that I was the perfect girl for him, but that a low credit score was his deal-breaker."

The credit score, once a little-known metric derived from a complex formula that incorporates outstanding debt and payment histories, has become an increasingly important number used to bestow credit, determine housing and even distinguish between job candidates.

It's so widely used that it has also become a bigger factor in dating decisions, sometimes eclipsing more traditional priorities like a good job, shared interests and physical chemistry. That's according to interviews with more than 50 daters across the country, all under the age of 40.

"Credit scores are like the dating equivalent of a sexually transmitted disease test," said Manisha Thakor, the founder and chief executive of MoneyZen Wealth Management, a financial advisory firm. "It's a shorthand way to get a sense of someone's financial past the same way an S.T.D. test gives some information about a person's sexual past."

It's difficult to quantify how many daters factor credit scores into their romantic calculations, but financial planners, marriage counselors and dating site executives all said that they were hearing far more concerns about credit than in the past. "I'm getting twice as many questions about credit scores as I did prerecession," Ms. Thakor said.

Executives who run online financial advice forums say that topics about credit and dating receive hundreds of responses within minutes of being posted. Alexa von Tobel, founder and chief executive of Learnvest.com, a financial planning firm, said that members are more interested in credit scores than ever before.

"It's the only grade that matters after you graduate," she said.

Josephine La Bella, 25, who works at a payroll company, likes to tackle the delicate subject head on. Ms. La Bella, who has vigilantly monitored her credit score ever since graduating from Rutgers in 2009, has found that broaching the topic of her own credit score causes her suitors to open up, too.

In August, Ms. La Bella recalled, while at dinner in Bayonne, N.J., a date blurted out his credit score on the first outing. Instead of making things more awkward, she said, a really productive discussion followed. Since then, Ms. La Bella tries to bring up the topic soon after meeting someone.

"I take my credit score seriously and so my date can take me seriously," she said. A handful of small, online dating Web sites have sprung up to cater specifically to singles looking for a partner with a tiptop credit score. "Good Credit Is Sexy," says one site, Creditscoredating.com, which allows members to view the credit scores of potential dates who agree to provide the numbers.

On another site, Datemycreditscore.com, a member posted on the Web site's home page that others should to "stop kidding" themselves and realize that credit scores do matter.

Dating someone with poor credit can have real implications. Banks remain wary of making loans to borrowers with tarnished scores, typically 660 and below; the best scores range from 800 to 850, and scores above 750 are considered good. A low score could quash dreams of buying a house, and result in steep interest rates, up to 29 percent, for credit cards, car financing and other unsecured loans.

A middling credit score can also torpedo an application for an apartment and drive up the cost of cellphone plans and auto insurance. And while eight states, including California, Illinois and Maryland, have passed laws limiting employers ability to use credit checks when assessing job candidates, 13 percent of employers surveyed by the Society of Human Resource Management in July performed credit checks on all job applicants.

Lauren Dollard, a 26-year-old assistant at a nonprofit in Houston, said her low credit score had helped to stall her romantic plans. Her boyfriend is wary of marrying her until she can significantly pay down the more than $150,000 she owes in student loans and bolster her credit score, she said.

Ms. Dollard's credit score is so low, around 600, that she hasn't been able to qualify for a car loan. She sympathizes with her boyfriend's position because he "doesn't ever want to be accountable for the irresponsible financial decision I made," she said. Her boyfriend declined to be interviewed.

John Hendrix, a 33-year-old chemist in San Francisco, said he worried that the vast disparity between his girlfriend's credit score and his own low one could create tension in their relationship. When the couple leased a car in October, Mr. Hendrix had to leave his name off the contract because his poor credit scuttled his chances for the bargain interest rate that his girlfriend qualified for.

Mr. Hendrix said he resented that his credit score, which he said was marred by a single contested cable bill, has limited his access to credit. "I always pay my bills so it's pretty ridiculous that a billing error can ruin your score," he said. His girlfriend declined to be interviewed.

Sarah Klein, who manages myFICO Forums, an online discussion group, likens credit scores to dieting because both affect dating but often are shrouded in secrecy. To motivate members to openly discuss and rehabilitate their credit scores, the site runs an online contest called the myFICO Fitness Challenge, where participants try to increase their scores. (FICO is a name derived from Fair Isaac Corporation.) Last year, more than 24,000 members participated.

In a post on the forum, one member asked for advice after finding out that her boyfriend's credit score hovered around 400. Some members denounced the member as petty and materialistic while others counseled her to run away from him.

Ms. LaShawn, the flight attendant from Chicago, said that she was still shocked that her credit score could sabotage a potentially great date. She had accumulated credit card debt and sporadically fallen behind on bills, and explained that she wasn't sure of her credit score, but was positive that it wasn't very good.

Days after her failed date, she said, she got an apologetic text message. Her date reiterated that the problem "wasn't me, it was my credit score."