Premarital sex is sexual activity practiced by people before they are married. Historically, premarital sex was considered a moral issue which was taboo in many cultures and considered a sin by a number of religions, but since about the 1960s, it has become more widely accepted, especially in Western countries. A 2014 Pew study on global morality found that premarital sex was considered particularly unacceptable in "predominantly Muslim nations", such as Malaysia, Indonesia, Jordan, Pakistan and Egypt, each having over 90% disapproval, while people in Western European countries were the most accepting, with Spain, Germany and France expressing less than 10% disapproval. Within Christianity, the Roman Catholic Church calls premarital sex a sin that must be forgiven through confession.
Until the 1950s, "premarital sex" referred to sexual relations between two people prior to marrying each other. During that period, it was the norm in Western societies for men and women to marry by the age of 21 or 22, and there was no considerations that one who had sex would not marry. The term was used instead of fornication, which had negative connotations, and was closely related to the concept and approval of virginity, which is sexual abstinence until marriage.
The meaning has since shifted to refer to any sexual relations a person has prior to marriage and removing the emphasis on the relationship of the people involved. The definition has a degree of ambiguity. It is not clear whether sex between individuals legally forbidden from marrying, or the sexual relations of one uninterested in marrying would be considered premarital.
Alternative terms for premarital sex have been suggested, including non-marital sex (which overlaps with adultery), youthful sex, adolescent sex, and young-adult sex. These terms also suffer from a degree of ambiguity, as the definition of having sex differs from person to person.