Since its launch in 1999, Taglit-Birthright Israel has brought more than 300,000 young adult Jews to Israel for 10-day educational experiences. Celebration of the program’s “bar mitzvah year” is a propitious moment to consider whether Taglit participants – many of whom are now 30-something adults – have chosen to make their Jewish identities a central part of their lives. Have the tens of thousands of participants who took part in Taglit as college students or recent graduates accepted citizenship in the Jewish world, with the attendant rights and responsibilities?Taglit was conceived to address the lack of connection of many young Jews to their heritage and the broader threat of assimilation. Even among those who celebrated bar/bat mitzvah, too many treated the adolescent rite of passage as the end of their engagement with Jewish life, not the opening of a door. For a Jewish community whose eldest members witnessed the Holocaust, the idea that 3,000 years of Jewish culture would assimilate away in the 21st century was an anathema.The writer is the Klutznick Professor of Contemporary Jewish Studies and Social Policy at Brandeis University. He directs the University’s Cohen Center for Modern Jewish Studies. email@example.comBut there was disagreement about how to respond. Taglit’s approach – to develop peer educational visits to Israel for unengaged young Jews – was initially considered radical.Views quickly changed in the face of overwhelming interest in Taglit and substantial evidence that, at least in the short term, the program “worked” to strengthen the Jewish identity of participants and their connection with Israel.Despite long waiting lists for slots on trips and a plethora of attitudinal data, until recently, it was not possible to assess whether participation in Taglit fosters adult engagement in Jewish life. Only now have large enough numbers of the Birthright Israel generation entered their 30s, married, had children and assumed full adult roles.My colleagues and I have been studying Taglit applicants from the early years of the program – both those who participated and others those who were waitlisted. Our initial findings were stunning.Although participants and nonparticipants were very similar at time of application, even five years later those who took part in Taglit were significantly more likely to say that they had a strong sense of belonging to the Jewish community and that they were highly connected to Israel as compared with peers who did not go on a trip.But even more telling, their behavior reflected stronger Jewish identity.The vast majority of married participants – 50 percent more than nonparticipants – decided to marry other Jews. And virtually all participants with children are raising them as Jews.As powerful as these findings were, the majority of those in our earlier studies had not yet married. And the oldest members of the population had participated in Taglit during the most difficult period of the second intifada. Would those who marry later and would those who went to Israel during a different period be impacted in the same way? Perhaps most importantly, as increasing numbers of alumni settle into full adult roles do they participate in the Jewish community?Our latest study, of nearly 2,000 individuals who applied to Taglit between 2001 and 2006, makes clear that traveling to Israel on Taglit is life-changing.Although six to 11 years have elapsed, as we found before, participants are more highly connected to Israel and more likely to be belong to a Jewish congregation. And, once again, more than 70% of non-Orthodox-raised Taglit alumni who had married were partnered with other Jews. Virtually all the inmarried alumni with children were raising them as Jews. In comparison, fewer than 50% of the non-participants had married other Jews, inflated because some of the non-participants married Taglit alumni.Some may wonder if endogenous marriage is an appropriate criterion. It wasn’t a direct goal of Taglit. Unlike other measures, however, it’s not subjective outcome and, as many alumni told us, their decision to marry another Jew or to ask a non-Jewish partner to convert was an outgrowth of the importance they attach to their Jewish identity. Marriage is one of the most important decisions we make in life and it is one of the first adult actions that has clear connections to Jewish identity.In Taglit’s early years, skeptics challenged the idea that a 10-day educational trip to Israel could have longterm impact. Childhood was seen as a critical period for Jewish education, essential to adult engagement. A brief intervention, no matter how intensive, was also seen as far too weak a dose to have impact. It will perhaps take a full generation to judge conclusively whether participation in a peer experience in Israel during young adulthood can alter trajectories of Jewish identity and life. But the latest evidence seems very powerful, even surprising to those of us who have long been students of the phenomenon.Becoming a bar or bat mitzvah is a celebratory moment. Like most other occasions that mark Jewish time, however, it is also a time of reflection.Mazel tov to Taglit, and to all those who shaped and supported the program for enabling hundreds of thousands of Diaspora Jews to experience Israel and Jewish life with their peers.The responsibility is now on the recipients of the gift of a Birthright Israel trip to be Jewish citizens, to take ownership of their Jewish identities, and to ensure that Jewish life and culture remain vibrant both in Israel and the Diaspora.