. Forty percent of cohabiting households include children, either the children of the relationship or the children that one or both partners bring to the relationship (U.S. Bureau of Census, 1998, Wu, 1995; Schoen. 1992).
. Median duration of cohabitation is 1.3 years (Bumpass and Lu, 1998; Wu, 1995; Schoen and Davis, 1992). Previously married persons cohabit more often than never-married; two-thirds of those separated or divorced and under age 35 cohabit. They are more likely than never-married cohabiting couples to have children in the household, and they are much less likely than never-married to marry their current partner or someone else (Wineberg and McCarthy, 1998; Wu, 1995; Bumpass and Sweet, 1989).
. Those not completing high school are almost twice as likely to cohabit as those who complete college. Forty percent of college graduates. however, do cohabit at some time. Only 26 percent of women with college degrees cohabit, compared to 41 percent of women without a high school diploma. The higher the level of education, the more likely the cohabitor is to marry the partner (Qian, 1998; Bumpass and Lu, 1998; Thornton, Axinn. Teachman. 1995; Willis and Michael, 1994).
. Women are likely to cohabit only once, and that with the person they subsequently marry; men are more likely to cohabit with a series of partners (Bumpass and Sweet, 1989, Teachman and Polanko, 1990).
. Individuals, especially women, who experienced disruption in their parents' marriage are more likely to cohabit than those who had parents with stable marriages (Axinn and Thornton, 1992; Kiernan, 1992; Black and Sprenkle, 1991; Bumpass and Sweet, 1989).
. Persons with low levels of religious participation and who rate religion of low importance are more likely to cohabit and less likely to marry their partner than those who consider religion important and practice it. There is no difference in frequency of cohabitation by religious denomination; there is a significant difference in cohabitation frequency by level of religious participation (Krishnan, 1998; Lye and Waldron, 1997; Thornton, Axinn and Hill, 1992; Liejbroer, 1991; Sweet, 1989).
. In general, those in cohabiting households are more independent, more liberal in attitude and more risk oriented than noncohabitors (Clarkberg, Stolzenberg and Waite, 1995; Cunningham and Antill, 1994; Huffman, Chang, Rausch and Schaffer, 1994; DeMaris and MacDonald, 1993).
3. What Are the Reasons for Cohabitation?
The declining significance of marriage as the center of family is in large part a result of growing secularization and individualization in first-world cultures. A version to long-term commitments is one of the identifying characteristics of these trends and a major reason for cohabitation. Key milestones previously associated with marriage, such as sexual relationships, childbearing and establishing couple households, now occur without marriage. Individuals choose to cohabit under the influence of these cultural values but also for very individual reasons. Some are seeking to ensure a good future marriage and believe that a "trial marriage" will accomplish this; many are simply together because it seems more economically feasible or because it has become the social norm. In general, cohabitors are' not a homogenous or monolithic group, however fully their general characteristics can be described. The reasons for choosing cohabitation are usually mixed: Cohabitation may be in equal parts an alternative to marriage and an attempt to prepare for marriage.
There are both broad cultural reasons and a range of individual reasons for cohabitation.
. The cultural reasons are descriptive of most first-world countries: changing values on family and decline in the importance of marriage (Bumpass, National Survey of Families and Households No. 66, 1995; Clarkberg, Stolzenberg and Waite, 1995; Parker, 1990).
. Declining confidence in religious and social institutions to provide guidance (Nicole and Baldwin, 1995; Thornton, Axinn and Hill, 1992).
. Delaying of marriage for economic or social reasons while sexual relationships begin earlier. Eighty-five percent of unmarried youth are sexually active by age 20. "Marriage no longer signifies the beginning of sexual relationship, the beginning of childbearing or the point at which couples establish joint households" (Bumpass, No. 66,1995). (Popenoe and Whitehead, 1999; Peplau, Hill and Rubin, 1993; Rindfuss and Van den Heuvel, 1990).
The individual reasons for cohabitation are varied: