During the 1950s and 1960s, increasing numbers of married women entered the labor force, but in 1963 the average working woman earned only 63 percent of what a man made. That year author Betty Friedan published The Feminine Mystique, an explosive critique of middle-class patterns that helped millions of women articulate a pervasive sense of discontent. Arguing that women often had no outlets for expression other than "finding a husband and bearing children," Friedan encouraged readers to seek new roles and responsibilities, to seek their own personal and professional identities rather than have them defined by the outside, male-dominated society.  

The women's movement of the 1960s and 1970s drew inspiration from the civil rights movement. It was made up mainly of members of the middle class, and thus partook of the spirit of rebellion that affected large segments of middle-class youth in the 1960s. Another factor linked to the emergence of the movement was the sexual revolution of the 1960s, which in turn was sparked by the development and marketing of the birth-control pill.  

Reform legislation also prompted change. During debate on the 1964 Civil Rights bill, conservatives hoped to defeat the entire measure by proposing an amendment to outlaw discrimination on the basis of gender as well as race. First the amendment, then the bill itself, passed, giving women a legal tool to secure their rights.  

Women themselves took measures to improve their lot. In 1966, 28 professional women, including Betty Friedan, established the National Organization for Women (NOW) "to take action to bring American women into full participation in the mainstream of American society now." By the next year, 1,000 women had joined; four years later membership reached 15,000. NOW and similar organizations helped make women increasingly aware of their limited opportunities and strengthened their resolve to increase them.  

Feminism, or organized activity on behalf of women's rights and interests, reached high tide in the early 1970s. Journalist Gloria Steinem and several other women founded a new magazine, Ms., which began publication in 1972. Between 1971 and 1976, Our Bodies, Ourselves, a handbook by a woman's health collective, sold 850,000 copies.  

Some activists pressed for ratification of an Equal Rights Amendment (ERA) to the Constitution. Passed by Congress in 1972, it declared, "Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex." Over the next several years, 35 of the necessary 38 states ratified it. The courts also promoted sexual equality. In 1973 the Supreme Court in Roe v. Wade sanctioned women's right to abortion during the early months of pregnancy -- a significant victory for the women's movement.  

In the mid- to late 1970s, however, the women's movement stagnated. It failed to broaden its appeal beyond the middle class. Divisions arose between moderate and radical feminists. Conservative opponents mounted a campaign against the Equal Rights Amendment, and it died in 1982 without gaining the approval of the 38 states needed for ratification.