Every day (except Saturday) five middle-aged women gather in the basement office of a brick building in Brooklyn’s Borough Park neighborhood to assure the survival of ultra-Orthodox Judaism. Black-hatted men and “modestly” dressed women come to them, some young, others less so, all single. These women, professional shadchanim, or matchmakers, ask the men and women about their family connections and education, who they know, where they pray. Careful attention is devoted to the shidduch (matchmaking) résumé, a short document that includes most of these details plus a photo and references.

The shadchanim dismiss their unmarried charges after the interviews, then huddle together in a dark room lined with ancient religious texts. Speaking in a mixture of English, Yiddish, and Hebrew, they rifle through their notes, searching for matches. They are helping the men and women—especially the women—fulfill the primary social responsibility of their community: to get married.

For the ultra-Orthodox, religious restrictions against the “mingling” of genders prevent singles from taking advantage of contemporary coupling opportunities. There are no dating websites, apps, or events. Marital aspirants meet almost exclusively through the intercession of shadchanim like this group in Borough Park. A matchmaker—usually a woman, but men provide the service as well—finds a match and informs the parents on each side. The parents then conduct “research” into the proposed spouse. They ask around about the other family’s connections, check to see if there are any divorces, or if any of the proposed relations have abandoned the community in favor of the secular world. If all goes well, the matchmaker makes an introduction.

One chilly afternoon this fall, I met with one of the five Borough Park matchmakers—let’s call her Raisy—in her basement sanctum. Raisy was a plump woman with bright blue eyes visible through the bangs of the sandy-colored wig she wears per Orthodox tradition. She sat behind a desk cluttered with spiral notebooks, stacks of dating questionnaires, and an old desktop computer that contained her database of single ultra-Orthodox Jews. Raisy was initially reluctant to talk to me—Orthodox communities tend to be wary of outsiders, and a good shadchan should be discreet—but the difficulties of her job eventually began to tumble out. The holy work of matchmaking, she said, had become so much harder of late.

She was referring to the so-called Shidduch Crisis that has in recent years caused a panic throughout Orthodox and ultra-Orthodox Jewish enclaves in New York and New Jersey. The crisis stems from two factors: the rapid growth of the ultra-Orthodox and the marriage-age differential between men and women in their communities. Ultra-Orthodox women are ready to marry typically by age 19, after a post-high-school year in seminary; the men continue their religious studies into their early twenties. That scenario, plus the rapid growth of these communities—an estimated 3 percent per year—means more 19-year-old women than 23-year-old men. The result: Some women in every cohort pass unwed through their conventional prime marrying years. This marital imbalance has been exacerbated by the overall growth of the community. Put simply, there are too many unmarried women. (Among Hasidic Jews, men and women generally marry at the same age, so this problem has not affected them.)