Marty Sack wasn't thinking about business on the morning of Sept. 11. He closed his office, went home and called his family.

"We closed because we didn't know what was going to happen next," says Mr. Sack, the co-founder of LunchDates, a Boston-based dating service. "We talked about whether or not we would open the following day and we decided that we would open. [Clients] were calling us. People wanted to talk."

Although few new people joined in the two weeks following Sept. 11, when activity picked up, there was a surprising twist. "We started to have a rapid increase in men, but not women," says Sack, who has run LunchDates for 20 years. He says that in the two months following Sept. 11, the number of men who joined went up 24 percent, while the number of women plummeted 37 percent.

Sack puzzled over the numbers, noting that his dating business tends to cater more to women. Borrowing from the popular book "Men are from Mars, Women are from Venus," Sack says maybe the reason for the post-9/11 switch was because men are "fixers" and women are "processors." Perhaps, Sack says, some single men felt they could "fix things about themselves – by trying to meet someone." Women, perhaps, needed time to think.

Sack said male clients seemed to become more focused on their search for a relationship. One client, a professor in the Boston area, began to see his social activities in a new way. "I look at activities I'm engaged in more in terms of relationships than the activity itself these days," he says. "For example, if I'm singing in a choir, the connection and depth of my relationships with the people around me have taken on far more importance than the singing itself."

Although the ratio women to men joining LunchDates eventually drifted back to its earlier pattern, Sack is certain the events of Sept. 11 reminded people of the importance of relationships. "There is nothing better to alleviate the fear of the unknown than being in a relationship," he says.

– Mary Murray, photo by Stuart S. Cox Jr.