The family unit is central to the Jewish religion and life. In biblical times, extended families lived together within a tribal structure, and polygamy was practiced. In post-biblical times, polygamy disappeared for the most part and was forbidden in Europe around the year 1000 (See Gerhsom, Rabbenu). Among both European and Sephardic Jews in Israel and elsewhere the tradition of extended families living in the same community and maintaining strong ties has continued to this day. In the U.S., however, because of the general trend of young adults relocating due to career opportunities, the extended family structure has broken down, negatively impacting Jewish continuity. The synagogue, especially through the havurah movement since the 1970’s, has had a certain measure of success in addressing this problem.