There are believed to be three different kinds of mitzvot: those that are inclusive to everyone (observing Shabbat), those that are gender based (having children), and those that are gender based but not related to biological differences (reading Torah).
The Mishnah teaches that women are required to follow nearly all the negative commandments (mitzvot lo taaseh), except trimming one’s beard and viewing the deceased (Kiddushin 33b). As for the positive commandments (mitzvot asay) women must perform virtually all the commandments not structured by time, and are exempted from those mitzvot that are restricted by time (mitzvot asay she’hazeman gerama). This is because of women’s traditional domestic roles of bearing children, raising a family, and fulfilling household responsibilities.
The law was designed to liberate women of obligations of mitzvot that they would find difficult. For instance, a woman is not required to pray in the morning, because it would be demanding for her to also pay attention to the children. Nevertheless, every Shabbat women are obligated to recite the prayer over the wine (Kiddush) because all Jews are required to “remember the Sabbath Day” (Exodus 20:8). Additionally, women are expected to light the Chanukah candles because both men and women observed the miracle of Chanukah. Some rabbis believe that women are naturally more spiritual than men, and therefore require less demanding religious mitzvot.
There is no definite agreement among rabbis as to which positive, time bound commandments women are not obligated to fulfill. However, many rabbis follow the view of Maimonides and the Talmud which specifically lists five time-bound mitzvot not required to be performed by women: residing in the sukkah, raising the lulav on Sukkot, listening to the shofar on Rosh Hashanah and Yom Kippur, and wearing tzitzit or tefillin. It is also stated in the Talmud that women are not obligated to count the Omer or say the Shema. Furthermore, women are not expected to study the Torah, which is not time-bound. All of these commandments that a woman is exempted are outside the realm of her domestic sphere. These commandments involve a public religious life removed from domestic life.
Since the Mishnah uses the expression “exemption,” many women voluntarily choose to perform time-bounded mitzvot. However, the Orthodox community has denied women the mitzvot of wearing tallit and tefillin, no matter whether they voluntarily choose to perform the mitzvot. Scholars also debate whether a woman is permitted to recite the suitable blessing that adjoins a mitzvah that she is electing to perform.
Maimonides also believed that a commandment fulfilled by a woman, who is not obligated, is less equal than when performed by a man who is required. Conversely, Rabbenu Tam argued that mitzvot are a united responsibility of the Jewish people and once a woman or man takes on a mitzvah they are accountable for all aspects of the obligation. This has become a highly contested issue of whether a woman can claim she is accepting the mitzvah on behalf of the community, such as reading from the Torah.
Most traditional communities have maintained that a woman may not release men’s obligations by voluntarily opting to perform a mitzvah required of men. This judgment is emphasized by the idea of k’vod ha-tzibbur or “honor of the community,” that a woman discharging men of their obligations brings embarrassment to the community. However, in egalitarian Conservative and Reform synagogues, women can read from the Torah and lead services, consequently releasing men of their obligations. In virtually all Conservative and Reform services women can also execute the mitzvah of being counted in a minyan, unlike in Orthodox congregations. In 1973, the Conservative movement decreed that the omission of women from the prayer service was discriminatory.
Sources: Eisenberg, Ronald L. The JPS Guide to Jewish Traditions. PA: Jewish Publication Society, 2004; Telushkin, Joseph. Jewish Literacy: The Most Important Things to Know About the Jewish Religion, Its People and Its History. NY: William Morrow and Co., 1991; Kolatch, Alfred J. The Jewish Book of Why/The Second Jewish Book of Why. NY: Jonathan David Publishers, 1989.