The first step in adapting the bar mitzvah ceremony to the needs of your interfaith family is talking to the rabbi or spiritual leader at the synagogue. Synagogues have varying requirements of prospective bar/bat mitzvahs (e.g., enrolling in Hebrew school for a certain number of years, studying with the cantor, community service projects, etc.) prior to the actual ceremony. Generally, these requirements will begin at least a year before the date of the actual bar or bat mitzvah.
Be aware that synagogues have very different opportunities and limitations for families to adapt the service to their needs. Some synagogues seek to keep the Shabbat service a public, communal affair and therefore restrict the amount of control the bar/bat mitzvah child and his/her family have over the service. Others allow families significant freedom in offering roles in the service to family members and friends.
As a general rule, the more liberal the movement to which the synagogue belongs, the more flexibility the congregation will allow in offering roles in the service to family members and friends. So Orthodox synagogues will offer the least flexibility, Conservative synagogues more and Reform and Reconstructionist even more.
Synagogues have different positions on what non-Jewish relatives (including parents) are allowed or not allowed to do during the service. It is important to discuss these issues with your rabbi or prospective rabbi before planning the ceremony. Unlike a wedding, you cannot mold a ceremony to your needs and then seek out a rabbi to perform it.
If, as in a typical Reform synagogue, you are offered the opportunity to make choices about the service, your child and you need to decide what?s most important. Is this a day that?s more about your extended family, and you therefore want to adapt services or readings to include them? Or is this a day more about your family?s Jewish choices, and you therefore want to keep a more traditional service? Should your child?s ceremony be one piece of a communal service, or the centerpiece of the service? No choice is right or wrong for everybody; it?s important to figure out what is right for your child and you.
Also, be aware that in Conservative and Orthodox synagogues, children born to non-Jewish mothers–or adopted children whose parentage can?t be verified–may be required to go through a conversion process prior to their bar or bat mitzvah. This process can involve circumcision (bris)–or, if a boy is already circumcised, a symbolic ritual circumcision (hatafat dam brit), a dipping in a ritual bath (the mikvah) and appearance before a ritual court of three rabbis (beit din). If you plan on having your bar or bat mitzvah in a Conservative or Orthodox synagogue, it is essential you discuss this issue with the rabbi well before the child?s bar or bat mitzvah.
The Bar/Bat Mitzvah Ideas and Primer for Interfaith Families is also available as a PDF document.