Marriage, also called matrimony or wedlock, is a socially or ritually recognised union between spouses that establishes rights and obligations between those spouses, as well as between them and any resulting biological or adopted children and affinity (in-laws and other family through marriage). The definition of marriage varies around the world not only between cultures and between religions, but also throughout the history of any given culture and religion, evolving to both expand and constrict in who and what is encompassed, but typically it is principally an institution in which interpersonal relationships, usually sexual, are acknowledged or sanctioned. In some cultures, marriage is recommended or considered to be compulsory before pursuing any sexual activity.