Family structures of some kind are found in every society. Pairing off into formal or informal marital relationships originated in hunter-gatherer groups to forge networks of cooperation beyond the immediate family. Intermarriage between groups, tribes, or clans was often political or strategic and resulted in reciprocal obligations between the two groups represented by the marital partners. Even so, marital dissolution was not a serious problem as the obligations resting on marital longevity were not particularly high.
One Parent Households
One recent trend illustrating the changing nature of families is the rise in prevalence of single-parent families. While somewhat more common prior to the twentieth century due to the more frequent deaths of spouses, in the late nineteenth and early twentieth centuries, the nuclear family became the societal norm in most Western nations. But what was the prevailing norm for much of the twentieth century is no longer the actual norm, nor is it perceived as such.
In the 1960s and 1970s, the change in the economic structure of the United States–-the inability to support a nuclear family on a single wage–-had significant ramifications on family life. Women and men began delaying the age of first marriage in order to invest in their earning power before marriage by spending more time in school. The increased levels of education among women, with women now earn more than 50% of bachelor's degrees, positioned women to survive economically without the support of a husband. By 1997, 40% of births to unmarried American women were intentional and, despite a still prominent gender gap in pay, women were able to survive as single mothers.
Cohabitation is an intimate relationship that includes a common living place and which exists without the benefit of legal, cultural, or religious sanction. It can be seen as an alternative form of marriage, in that, in practice, it is similar to marriage, but it does not receive the same formal recognition by religions, governments, or cultures. The cohabiting population, although inclusive of all ages, is mainly made up of those between the ages of 25 and 34. In 2005, the U.S. Census Bureau reported 4.85 million cohabiting couples, up more than 1,000% from 1960, when there were 439,000 such couples. More than half of couples in the United States lived together, at least briefly, before walking down the aisle.
While homosexuality has existed for thousands of years among human beings, formal marriages between homosexual partners is a relatively recent phenomenon. As of 2009, only two states in the United States recognized marriages between same-sex partners, Massachusetts and Iowa, where same-sex marriage was formally allowed as of May 17, 2004 and April 2009, respectively. Three additional states allow same-sex civil unions, New Jersey, Connecticut, and Vermont. Between May 2004 and December 2006, 7,341 same-sex couples married in Massachusetts. Assuming the percentage of homosexuals in Massachusetts is similar to that of the rest of the nation, the above number indicates that 16.7% of homosexuals in Massachusetts married during that time. Massachusetts is also the state with the lowest divorce rate.
Same sex couples, while becoming increasingly more common, still only account for about 1 percent of American households, according to 2010 Census data. About 0.5 percent of American households were same-sex couples in 2000, so this number has doubled, and it is expected to continuing increasing by the next Census data.
Voluntary childlessness in women is defined as women of childbearing age who are fertile and do not intend to have children, women who have chosen sterilization, or women past childbearing age who were fertile but chose not to have children. Individuals can also be "temporarily childless" or do not currently have children but want children in the future. The availability of reliable contraception along with support provided in old age by systems other than traditional familial ones has made childlessness an option for some people in developed countries. In most societies and for most of human history, choosing to be childfree was both difficult and undesirable. To accomplish the goal of remaining childfree, some individuals undergo medical sterilization or relinquish their children for adoption.
Household types in the United States in 2006
This figure shows that roughly 5% of households in the United States are made up of cohabiting couples of various types: heterosexual, gay, or, lesbian.