Homosexual behaviour

Human sexual activity has sociological, cognitive, emotional, behavioural and biological aspects; these include personal bonding, sharing emotions and the physiology of the reproductive system, sex drive, sexual intercourse and sexual behaviour in all its forms. In some cultures, sexual activity is considered acceptable only within marriage, while premarital and extramarital sex are taboo. Some sexual activities are illegal either universally or in some countries or subnational jurisdictions, while some are considered contrary to the norms of certain societies or cultures. Two examples that are criminal offences in most jurisdictions are sexual assault and sexual activity with a person below the local age of consent. Sexual activity can be classified in a number of ways: acts which involve one person (also called autoeroticism) such as masturbation, or two or more people such as vaginal sex, anal sex, oral sex or mutual masturbation. Penetrative sex between two people may be described as sexual intercourse, but definitions vary. If there are more than two participants in a sex act, it may be referred to as group sex. Autoerotic sexual activity can involve use of dildos, vibrators, butt plugs, and other sex toys, though these devices can also be used with a partner. Sexual activity can be classified into the gender and sexual orientation of the participants, as well as by the relationship of the participants. For example, the relationships can be ones of marriage, intimate partners, casual sex partners or anonymous. Sexual activity can be regarded as conventional or as alternative, involving, for example, fetishism, paraphilia, or BDSM activities. Fetishism can take many forms ranging from the desire for certain body parts, for example large breasts, navels or foot worship. The object of desire can often be shoes, boots, lingerie, clothing, leather or rubber items. Some non-conventional autoerotic practices can be dangerous. These include erotic asphyxiation and self-bondage. The potential for injury or even death that exists while engaging in the partnered versions of these fetishes (choking and bondage, respectively) becomes drastically increased in the autoerotic case due to the isolation and lack of assistance in the event of a problem. Sexual activity can be consensual, which means that both or all participants agree to take part and are of the age that they can consent, or it may take place under force or duress, which is often called sexual assault or rape. In different cultures and countries, various sexual activities may be lawful or illegal in regards to the age, gender, marital status or other factors of the participants, or otherwise contrary to social norms or generally accepted sexual morals. In evolutionary psychology and behavioral ecology, human mating strategies are a set of behaviors used by individuals to attract, select, and retain mates. Mating strategies overlap with reproductive strategies, which encompass a broader set of behaviors involving the timing of reproduction and the trade-off between quantity and quality of offspring (see life history theory). Relative to other animals, human mating strategies are unique in their relationship with cultural variables such as the institution of marriage. Humans may seek out individuals with the intention of forming a long-term intimate relationship, marriage, casual relationship, or friendship. The human desire for companionship is one of the strongest human drives. It is an innate feature of human nature, and may be related to the sex drive. The human mating process encompasses the social and cultural processes whereby one person may meet another to assess suitability, the courtship process and the process of forming an interpersonal relationship. Commonalities, however, can be found between humans and nonhuman animals in mating behavior (see animal sexual behavior). The physiological responses during sexual stimulation are fairly similar for both men and women and there are four phases.