The establishment of duties within a social group, based on sex, is known as the sexual division of labor. The early 20th century brought about many striking changes for the United States, providing similarities and differences from the mid-20th century regarding women in the workplace. The early 20th century spans from approximately 1901 to 1933 and is known as a period of urban and industrial modernization, which brought many opportunities for women. However, this era also brought many challenges, especially with organizing women in trade unions. The women faced great opposition from their male colleagues. The mid-20th century spans from approximately 1934 to 1967 and gave rise to many social movements based on the movements of the early 20th century. The transition of women in the workplace went from temporary, unorganized, unskilled, and exploited workers in the early 20th century to permanent, educated, organized, and protected workers in the mid-20th century. “When we stop asking why women haven't organized, we are led to ask how women have been, and are, kept out of unions” (Kessler-Harris, 94). The cult of domesticity has grown alongside the advancement of the American middle class. Women of this time were expected to be selflessly emotional, morally pure, and submissive in their roles as mother and wife, while the husband supported his family financially as he was seen as intellectually superior. Although women gained moral authority, they were limited to a life of economic dependence and limited role choices. Men typically condemned work outside the home and expected the wife to provide a domestic refuge of purity and devote her life to unpaid work within the home. Limitation of long working hours for women should be imposed where and when the union is not strong enough to limit hours. In 1927, Fannia Cohn admitted that in the absence of unionization among women, it would be unwise to disagree with protective legislation. “Limited workforce opportunities, protective labor legislation, and virtual exclusion from unions institutionalized women's isolation from the labor mainstream.” and confirmed the assumed role of women in society (Kessler-Harris, 105). Although many recognized that competition between men and women in the workplace was futile for all workers, and during the first two decades of the twentieth century, unreasonable and non-economic arguments prevailed that eased women's stress somewhat, but at the same time established their place in working life. jobs more subject to exploitation.