The responsible fatherhood movement encourages fathers to be involved in their children's lives and advocates for societal support of such involvement. The rise of single-parent homes The number of children living in single-parent households has increased since the 1960s. Approximately 9% of children under 18 lived with a single parent in 1960; by 2007 this rate had increased to nearly 32%. The largest growth occurred between 1970 and 1985, when the growth of single-mother families leveled off. This shift is attributed to a variety of widely recognized social changes that occurred in American society in the 1960s and 1970s: changing sexual morals increased the prevalence of sexual activity outside of marriage and decreased the stigma surrounding out-of-wedlock births; American attitudes about marriage and divorce changed; and women made economic gains that increased their independence and ability to leave unhappy marriages. While the social science community of the 1960s and 1970s initially regarded single-mother households as "just another alternative family form", evidence began to surface in the late 1970s demonstrating that children raised in households where the father was absent were disadvantaged relative to other children. In 2008 in the United States there were an estimated 28 million children growing up in households without fathers. The rise of the responsible fatherhood movement in the U.S. Along with the changes in family formation in the latter part of the 20th century, the issue of healthy, responsible fatherhood also began to gain attention. In 1974, Dr. James A. Levine published Who Will Raise the Children? New Options for Fathers (and Mothers). In this report, "Levine suggested that the long-term goal of equal opportunity for women in American society would never be achieved without serious and meaningful recognition of the significance, interest, and responsibility of fathers in children's lives. Levine called for changes in major social institutions, changes in how families raise boys and girls, and changes in the mutual expectations of men and women as they form families." Throughout the 1980s and 1990s, a national responsible fatherhood movement began to take form in the United States. "Within this 'movement,' one may discern a range of groups with competing masculinities and contesting claims and grievances....[T]he Fatherhood Responsibility Movement seeks to overcome barriers of income, race and politics." As the responsible fatherhood movement has matured, educational and social service programs have grown to meet the needs of fathers across the country. For example, in 1981,