Research into the causes and consequences of occupational segregation, the gender pay gap, and the "glass ceiling" have been a significant part of feminist economics. While conventional neoclassical economic theories of the 1960s and 1970s explained these as the result of free choices made by women and men who simply had different abilities or preferences, feminist economists pointed out the important roles played by stereotyping, sexism, patriarchal beliefs and institutions, sexual harassment, and discrimination.[72] The rationales for, and the effects of, anti-discrimination laws adopted in many industrial countries beginning in the 1970s, has also been studied.[73]