Monogamy, derived from the Greek words "monos" (single) and "gamos" (marriage), most technically refers to the state or practice of being married to only one person at a time but is also commonly used to describe having only one romantic or sexual partner at a time. It stands in contrast to non-monogamous relationships like polygamy or polyamory. While often associated with marriage, monogamy can also refer to exclusive relationships outside of marriage.
There are different types of monogamy, including social, sexual, and genetic monogamy. Social monogamy involves cohabitation, shared resources, and a sexual relationship, while sexual monogamy refers to having no outside sexual partners. Genetic monogamy implies sexual exclusivity with genetic evidence of paternity. Serial monogamy is a pattern of having consecutive exclusive relationships over time.
The evolution of monogamy in humans is likely due to a combination of biological and cultural factors, such as the need for paternal care, ecological pressures, and the development of agriculture and property inheritance. Some studies suggest a shift towards monogamy in early humans around 3.5 million years ago. However, only a minority of societies are strictly monogamous, with many practicing serial monogamy or tolerating extramarital sex.
Despite being culturally expected and rewarded, only about 3-5% of mammals are monogamous. In the United States, a growing number of people are open to non-monogamous relationships. A 2025 survey found that 61% of Americans would consider non-monogamy, with Gen Z being the most open to it.
