Rabbi Binyamin Sanders knew the crisis had reached his doorstep when the phone calls began — and didn’t stop.

Looking for matches for their single young daughters, mothers and fathers call the Yeshiva of Greater Washington, where Sanders is the director of development, and one of the few places in the D.C. region with a high concentration of religiously educated Orthodox young men. If they don’t know anyone who works at the Silver Spring school, they will call someone who does.

“It’s so pervasive, I’m amazed,” said Sanders, who is in the thick of trying to find matches for his own daughters, 22 and 24.

The Orthodox call it the “shidduch crisis,” or matchmaking crisis — a perceived rise in the number of male and female singles, a delay among those in their 20s in marrying and a struggle to meet a match. In a community that forbids premarital sex and is centered on family, “this is considered one of the major crises in Judaism,” said Sanders.

And with the start Monday night of Passover, a holiday that revolves around gathering one’s relatives for long, story-telling ritual meals, the presence of young unmarried Jews at the table only heightens the angst.

There are “emergency shidduch conferences,” training sessions for parents, new dating Web sites and businesses offering cash for people who pull off successful set-ups.

Among them is Star-K, a major kosher certification firm in Baltimore, home to the country’s largest per capita Orthodox community in the country. After giving out more than $350,000 — $2,500 a pop – over the past five years for people who make successful matches, the firm announced a few weeks ago it needed to start investing its charitable dollars elsewhere. But it noted that the program has been replicated in New York, New Jersey and Toronto.

Finding a match already had its challenges for people from a tiny community that marries from within.

Orthodox Jews make up less than than 10 percent of American Judaism, with an estimated population between 300,000 and 750,000 people. Being unmarried into your mid-20s in this world can be isolating.

“It’s very lonely to be single,” said Sara Herst, a 23-year-old who grew up in Silver Spring and now works at a religious school in Massachusetts. “When you go to shul [synagogue], everyone is young couples.”

Not everyone agrees that Herst’s situation poses a challenge for Judaism. There is no data on how many Orthodox Jews are delaying or opting out of marriage. And the definition of “crisis” varies among “modern Orthodox” and the ultra-Orthodox, or haredim.

Queens College sociologist Samuel Heilman, who has written extensively on Orthodox Judaism, said the haredim are growing as a proportion of the Orthodox, and now may make up as much as 40 percent. This sector’s ability to frame later marriage or singledom as a “crisis” shows they are controlling the discussion, he said.

“It is all about the contest for the future of orthodoxy and who will define what is normative and optimal,” he wrote in an e-mail.

Among those who are alarmed about the singles situation, opinions abound about the cause.

Is an increased conservatism that keeps the genders apart at everything from wedding receptions to lectures the reason more people are single? Has the recent growth boom in Orthodox schools produced young women who believe a suitable husband has to be practically a Talmudic scholar? Have dating Web sites — some of which are chaperoned by matchmakers, or shadchans — helped or hurt by creating an open marketplace with endless, superficial expectations that didn’t exist a decade or two ago?

Some experts see a broader shift in play among other faiths. The shidduch crisis, they say, is really a collision between traditional orthodoxy, which prioritizes expanding Jewish families and community preservation, and a secular, individualistic Western ethos that celebrates other successes.

“The Orthodox in the United States are torn between two cultural values,” said Larry Grossman, editor of the American Jewish Year Book, a major annual record of trends in the community. “Their ‘American’ side, which you can’t avoid, is saying: There’s nothing wrong with self-fulfillment, that you have value in terms of choosing a profession, a lifestyle.”

While community leaders first began voicing concern about the increased number of singles several years ago, Grossman said the issue is “becoming more acute.”

Even so, some have lashed out at the framing of the subject, arguing that young Orthodox delaying marriage because they have more personal and professional options should not be seen as a problem.

Jewish law, this camp says, doesn’t mandate an SUV-load of babies, and most couples in the Bible didn’t meet through a matchmaking system that assumes men and women shouldn’t mix too freely. They have launched Web sites with names like endthemadness.org and written satire pieces like one about Shidduch Crisis Anonymous.

Psychologist Michael Salamon, who runs a mental health clinic on Long Island that caters to the Orthodox, says he believes the intense pressure to marry combined with new barriers to gender mixing is leading to incompatible matches, increased divorce, domestic violence and eating disorders.

He writes and lectures against things like the Star-K bounty — which he calls “totally manipulative” — and says he gets hate mail.

“Who says you have to be married by a certain age? Who says you have to have so many children? Under Jewish law, two children meets all the requirements,” he said. “Rabbinical tradition encourages questioning and looking for your own answers.”

To Harris Cohen, a 28-year-old project manager at Amtrak who lives in Silver Spring, the issue boils down to one word: pickiness.

To him the plethora of options on-line dating has opened and the demand by many for a more observant partner is creating a crisis, rather than any stigma in the modern Orthodox community of which he is part.

“In the past people weren’t as discerning — as long as someone was observant, that was acceptable. Today there are other criteria people are focusing on,” said Cohen, who recently started dating someone.

The Sanders Passover table tonight will include his two single daughters, including 22-year-old Leah, who says finding a match isn’t easy in an era when men and women have little chance to mix.

“Girls don’t know the boys and boys don’t know girls, how are they supposed to meet each other?” For her part, she won’t discuss if she is dating.

“Personally, I don’t feel pressure, but I know a lot of people who do at my age. All your friends are married, and you’re by yourself.”