As Birthright Israel has grown drastically since starting operations in 2000 - it has brought over 180,000 young adults to Israel - the question of eligibility for the free trips has become more controversial. According to reports, an increasing number of non-Jewish participants, including devout Christians, have managed to get through the screening process of the program, which is meant for Diaspora Jews between 18 and 26 who have never participated in an organized visit here. "There were two Christians on my trip, and they didn't hide it at all," 2006 Birthright participant Elissa Glick told The Jerusalem Post on Monday. "They carried New Testaments and protested when we didn't visit the Holy Sepulchre. They were totally segregated from the group." According to Birthright Israel's Web site, participants are eligible if they are recognized as Jewish "by the Jewish community or by one of the recognized denominations of Judaism, or if either parent is Jewish and the applicant does not actively practice another religion." But it is evident that this criteria is not always used when selecting participants. "I think a lot of the times it was just a matter of trying to get as many people as you can, and I think there are a lot of people who slip through the cracks," said an anonymous former night shift interview manager for a Birthright program from March to November 2007. "One of the questions we had to ask was 'what is your favorite holiday memory?' And people are telling us: Christmas with my family... But we are still saying 'okay, you can come on the trip," the manager said. According to Tim, a 24-year-old New Jersey native who just completed a Mayanot Birthright trip, his mother's family is Jewish, but he was raised as a Christian Scientist. "My mother's family is Jewish, but they converted in the 1920s. Our whole family gets together to celebrate Christmas... I am definitely a member of a Christian family," he said. When asked why he went on the trip, Tim explained: "It was more of a cultural heritage trip for me... I am not a supporter of organized religion, I really don't like it." Gidi Mark, director of marketing for Taglit-Birthright Israel, admitted that mistakes had been made in the selection process. "We send about five [participants] home every season out of 40,000... We catch about 100 every year before they come... We have improved the registration process a lot over the last two years," he said. He added that Birthright had "a very sophisticated screening and interviewing process that has proven itself very well... There are some key questions that put you in a category that may require the interviewer to ask you some more questions." The manager explained, "When we were doing interviews there was a lot of fine very lines... We would have to say... all of these other answers were correct, but really just this one little thing was flagged... so we would flag them to be re-interviewed... but who ever knows if they were, or if they were just put on a plane." While it is understood that there are participants every year who take advantage of the system, the implications are less clear. "From a larger organizational perspective, if you have 20,000 participants and even 200 or 2,000 somehow trick their way through the eligibility requirements, I think it would be considered an acceptable failure percentage, for lack of a better term, that any organization would accept," said Jacob Shwirtz, head of the Birthright Alumni Association in Israel. "I think participants understand that this is a gift... so I think the percentage of people who abuse it is very small," said Jay Rosen, formerly involved in staffing Hillel Birthright trips in Washington, DC. "I really don't give it much thought." "We don't decide who is Jewish, we decide who is eligible for Birthright," Mark said when asked if the eligibility requirements should be stricter. Registration closed early this year due a record number of applications, and 20,000 on the waiting list for this summer's trips.