The History Of Mixed Seating

Rabbi Shlomo Brody writes in the Jerusalem Post:

The controversy over mixed seating was undoubtedly one of American Jewry’s most controversial and divisive issues. Since both the Orthodox and Conservative movements claim allegiance to ancient practice, some tried to resolve this debate by examining relics of ancient synagogues. It remains clear, however, that medieval and early modern synagogues had separate sections for men and women, with the latter seated in a separate section, gallery or adjacent room. While Orthodox decisors claim that this historical precedent sufficiently creates an inviolable minhag, their liberal detractors contend that the legal system includes room for more flexibility.

While the Temple had a so-called "Women’s Courtyard," some men entered this area for different purposes, such as the Torah reading on Yom Kippur and the Hakhel ceremony (Sota 41b), while women crossed the main "Israelites courtyard" to bring certain sacrifices (Bikkurim 1:5, 3:6). Most Orthodox proponents of a mehitza point to a different Temple ceremony to show the necessity of gender separation. In describing the seating during the festive water drawing ceremony of Succot, the sages taught, "Originally, women were inside [the gates of the Women’s Courtyard] and men were outside, and they came to frivolity. Orthodox proponents of the mehitza cite this enactment against frivolity as requiring gender separation in synagogues, since Jewish law frequently cites these new houses of worship as "mini sanctuaries."

While Rabbi Moshe Feinstein (d. 1986) argued that erecting a biblical-level law requires an actual physical barrier (Igrot Moshe 1:39), Rabbi Joseph Soloveitchik (d. 1993) asserted that the barrier itself stems from rabbinic mandate, with the original law only requiring physical separation (Sanctity of the Synagogue, p. 141).

 In 1851, the first American Reform synagogue instituted mixed pews after purchasing its new temple from a church. Orthodox rabbis, however, took an uncompromising stand, deeming such practices beyond the pale. While their seminary graduates continued, until the 1980s, to take positions in synagogues with mixed pews, they frequently demanded, over time, that the synagogue add a mehitza. This partition thus created a clear division between Orthodox and Conservative synagogues, a barrier which came to physically separate men and women and, symbolically, Jew from Jew.