Orthodox Judaism is based on gendered understandings of Jewish practice - i. e., that there are different roles for men and women in religious life. This reflects the view that everyone is created "unique" (i.e., not "equal"); this emphasizes the view that everyone is created with a specialized, unique role in the world. There are different opinions among Orthodox Jews concerning these differences. Most claim that men and women have complementary, yet different, roles in religious life, resulting in different religious obligations. For example, women are not burdened with time-bounded mitzvahs. Others believe that some of these differences are not a reflection of religious law, but rather of cultural, social, and historical causes. In the area of education, women were historically exempted from any study beyond an understanding of the practical aspects of Torah, and the rules necessary in running a Jewish household, both of which they have an obligation to learn. Until the twentieth century, women were often discouraged from learning Talmud and other advanced Jewish texts. In the past 100 years, Orthodox Jewish education for women has advanced tremendously. This is most embodied in the development of the Bais Yaakov system.