A family is defined by the

United States Census Bureau The United States Census Bureau, officially the Bureau of the Census, is a principal agency of the Federal statistical system, U.S. federal statistical system, responsible for producing data about the American people and American economy, econ ...

for statistical purposes as "a group of two people or more (one of whom is the householder) related by birth, marriage, or adoption, and residing together; all such people (including related subfamily members) are considered as members of one family." A family household is more inclusive, consisting of "a household maintained by a householder who is in a family (as defined above), and includes any unrelated people (unrelated subfamily members and/or secondary individuals) who may be residing there." In 2014, the US Census Bureau began including

same-sex marriages Same-sex marriage, also known as gay marriage, is the marriage of two people of the same legal sex. marriage between same-sex couples is legally performed and recognized in 38 countries, with a total population of 1.5 billion people (20% ...

in their counts of families and family households. Prior to this, they were counted as cohabiting partners; thus, they were not considered as forming a family.Cohn

Notes

References

* *{{cite web, last1=Cohn, first1=D’Vera, title=Census says it will count same-sex marriages, but with caveats, url=http://www.pewresearch.org/fact-tank/2014/05/29/census-says-it-will-count-same-sex-marriages-but-with-caveats/, website=Pew Research Center, date=May 29, 2014 Family in the United States United States Census Bureau