Marriage is a legally and socially sanctioned relationship between two or more people (though typically two), involving economic cooperation, emotional intimacy, and often normative sexual activity and child-bearing, which the individuals and society expect to be enduring or relatively permanent. The definition and practices of marriage vary significantly across cultures and have evolved over time, with changes in who can marry (e.g., same-sex marriage), the purposes of marriage (beyond procreation to include companionship and personal fulfillment), and the prevalence of different forms of marriage (e.g., monogamy, polygamy). Marriage often establishes kinship ties and defines rights and obligations between spouses and their families. It is a fundamental social institution that plays a crucial role in regulating sexual behaviour, organizing family life, and transmitting social status and property across generations.