Significant age isparity in sexual relationships has been and remains a feature of couples in many cultures and societies. The most common pattern in heterosexual couples is an older man with a younger woman. This may be brought about as an arranged marriage, or either member may pursue and initiate the relationship. Relationships involving a younger male and an older female also exist, and while not as common, have become considerably more common in recent years.Homosexual relationships of both sexes may also exhibit age disparity; when between an adult male and adolescent boy, the term "pederasty" is sometimes used, especially in European historical context. In extreme cases, age disparity may be seen as dysfunctional (a paraphilia) if such relationships are pursued to the exclusion of all others and to the detriment of the partners. Sexual relationships involving an adult or adolescent and a prepubescent child are defined as child sexual abuse in all modern societies.