On a recent afternoon, Diana Blau, 22, was relaxing on the beach after bathing in the salty waters of the Dead Sea.
Blau's mother is Jewish and her father Greek Orthodox. She has never strongly identified with Jewish culture or religion, she said, in part because she doesn't regularly attended synagogue and didn't grow up with many Jewish friends.
"There's a disconnect," said Blau, a graphic designer from Emerson, N.J. "I'm usually the only Jew in the room."
In many ways Blau is the target demographic for Taglit-Birthright, which provides free trips to the Holy Land for Jewish young adults ages 18 to 26. In recent years, the program has been redoubling its efforts to help keep Jewish tradition afloat amid increasing anxiety that young members of the Jewish diaspora are losing their connection to their culture and to Israel.
One recent survey by the Pew Research Center found that one-third of Jews under 30 said being Jewish was very important to them. That compares with 54% of Jews 65 and older.
Intermarriage, long viewed as a threat to American Judaism, also continues to increase. Of survey respondents married since 2000, nearly 6 in 10 had wed a non-Jew, compared with 4 in 10 among those who married in the 1980s and 2 in 10 among those who married before 1970.
Offering Jewish young adults a chance to experience Israel together may change that.
A recent Brandeis University survey on Birthright found that participants were more than 45% more likely to marry someone Jewish, a statistic that underscores one of the program's main goals: introducing Jews to one another. Birthright encourages participants to socialize, and it also places young Israeli soldiers on every tour bus.
Birthright donor Michael Koss, a real estate investor in West Los Angeles, said introducing Jews to one another is essential to preserving "the continuity" of Judaism.
"If there isn't any kind of connection made, then Jews will intermarry," he said. "And eventually there won't be Jews any more."
Created in 1999 by Seagram spirits heir Charles Bronfman and hedge fund manager Michael Steinhardt, Birthright has recently expanded through donations of more than $200 million each from Las Vegas casino magnate and Republican fundraiser Sheldon Adelson and the Israeli government. Last year, the program sent 44,000 people to Israel, double the number four years ago.
During that time, the program has also loosened its eligibility requirements, allowing some of those who have previously traveled in a group to Israel to participate. It has also sought to broaden its appeal by reaching out to niche groups. It now offers specialized trips for those who love the outdoors and culinary tours designed for foodies, including an evening in which participants cook a meal for Israel Defense Forces soldiers. Other targeted tours cater to animal lovers, lacrosse players, first responders, and the gay, lesbian, bisexual and transgender community.
Blau, who acknowledges that she probably would never have come to Israel if it weren't for a free Birthright trip, was one of three dozen young Americans and Canadians between the ages of 18 and 26 who crisscrossed the country by bus this year.
The group had been in Israel for less than two days, but already its members had prayed at the Western Wall, slept in a tent in the Negev desert, climbed to the top of the ancient fortress of Masada and ridden camels.
Walking through the stone gates to Jerusalem's Old City, 26-year-old Sam Paul said his emotions surprised him.
"It was a spiritual experience I didn't expect to get," said Paul, an insurance broker from Manchester, N.H.
For David Weingrad, 26, of Merrick, N.Y., being in Israel had reaffirmed his pro-Israel stance. "We were here first, it's our land," he said. "We belong here."
Critics of the program describe it as a vehicle for Israeli propaganda that seeks to downplay the conflict with Palestinians. Some have started an alternative program called Birthright Unplugged that includes extensive tours of the Palestinian territories, which the original Birthright leaves off its itinerary.
The tour guide leading the Birthright trip that Blau and Paul joined said he makes a point of taking his groups to the barrier that divides Israel and the West Bank. Guide Ayal Beer said he also emphasizes Israel's domestic complexities, including tensions between the country's secular and ultra-Orthodox Jewish communities.