The chief threat to the Reform movement in America is the reluctance of young Jews to join community institutions, says its outgoing head.

There is a "general process of non-affiliation" rooted in an "anti-institutional era in American life", according to Rabbi Eric Yoffie, president of the Union for Reform Judaism.

"We have to cope with a tide of modernity that has swept over our community. Young people don't tend to be joiners, much less have a tendency to affiliate with an institution. So we need to work hard to overcome those demographic and sociological realities."

Earlier this month Rabbi Yoffie announced that he would relinquish his post in 2012, when he is 65, after a 14-year term. This would give the URJ two years to find a replacement head for the largest organised Jewish movement in America.

According to the most recent National Jewish Population Survey, conducted in 2000, 34 per cent of Americans identify as Reform - roughly equivalent to the Liberals in the UK - compared to 26 per cent who identify as Conservative and 13 per cent who identify as Orthodox. (About one quarter of respondents identified as "Just Jewish".) URJ has an estimated 1.5 million members.

Despite its strength, America's Reform movement has struggled in recent years. Membership has stalled, fewer people are converting and many Reform synagogues, like in other Jewish denominations, suffer from dwindling congregations and financial pressures exacerbated by the recession.

Under Rabbi Yoffie's presidency, the Reform movement has re-embraced certain traditional elements, such as the inclusion of more Hebrew in services. Jonathan Sarna, a Jewish history professor at Brandeis University, wrote in a recent essay for the Forward that Rabbi Yoffie had made "Reform Judaism more Jewish".

Regardless of current difficulties, Rabbi Yoffie is optimistic about the movement's future, particularly because of its inclusivity. Reform synagogues welcome gays, converts and even partners who do not wish to convert.

"I am convinced that our particular blend of modernity and tradition will put us in the best position to respond," said Rabbi Yoffie, adding that the primary focus of his final two years will be to revitalise Reform's youth movement. "We lose a very high percentage of kids from 13 to 18," Rabbi Yoffie said. "We have a committed core who are engaged in a youth movement. The issue for us is can we extend our reach?"

Over his presidency, Rabbi Yoffie has been an outspoken critic of the Orthodox religious monopoly in Israel.

Citing recent demonstrations in Jerusalem by strictly Orthodox Jews protesting the integration of Ashkenazi and Sephardi schoolgirls, Rabbi Yoffie said the domination of Orthodox Judaism has been "bad for Israel and bad for the Jewish people".

"Torah is the collected wisdom of the Jewish people," said Rabbi Yoffie. "Yet for many Israelis, Torah is associated with corrupt political parties, with coercive religious practices, with conversion that is virtually impossible to carry out under any circumstances, with an unwillingness to serve in the army to meet the ongoing obligations of defence of one's country, with a failure to work and support your family and with the expectation that the government will do it for you. Ultimately, it has brought Torah into disrepute."

He added: "I humbly suggest there's not a single example anywhere in human history of a coercive religious monopoly that ends up benefitting a religious tradition in whose name it was created."