A paraphilia is an experience of recurring or intense sexual arousal to atypical objects, places, situations, fantasies, behaviors, or individuals.

[9][10] Several sub-classifications of paraphilia have been proposed; some argue that a fully dimensional, spectrum, or complaint-oriented approach would better reflect the evident diversity of human sexuality.

[11][12] Although paraphilias were believed in the 20th century to be rare among the general population, recent research has indicated that paraphilic interests are relatively common.

[16][17][18] To date there is no broad scientific consensus for definitive boundaries between what are considered "unconventional sexual interests", kinks, fetishes, and paraphilias.

Many terms have been used to describe atypical sexual interests, and there remains debate regarding technical accuracy and perceptions of stigma.

"[22] Psychiatrist Glen Gabbard writes that despite efforts by Wilhelm Stekel and John Money, "the term paraphilia remains pejorative in most circumstances.

"[23] In the late 19th century, psychologists and psychiatrists started to categorize various paraphilias as they wanted a more descriptive system than the legal and religious constructs of sodomy,[24] as well as perversion.

They are ... hyperbolic intensifications, distortions, monstrous fruits of certain partial and secondary expressions of this erotism which is considered 'normal' or at least within the limits of healthy sex feeling.

[27] In 1981, an article published in American Journal of Psychiatry described paraphilia as "recurrent, intense sexually arousing fantasies, sexual urges, or behaviors generally involving" the following:[28] Clinical literature contains reports of many paraphilias, only some of which receive their own entries in the diagnostic taxonomies of the American Psychiatric Association or the World Health Organization.

[32] There is scientific and political controversy regarding the continued inclusion of sex-related diagnoses such as the paraphilias in the DSM, due to the stigma of being classified as a mental illness.

Charles Allen Moser, a physician and advocate for sexual minorities, has argued that the diagnoses should be eliminated from diagnostic manuals.

A 2008 study analyzing the sexual fantasies of 200 heterosexual men by using the Wilson Sex Fantasy Questionnaire exam determined that males with a pronounced degree of fetish interest had a greater number of older brothers, a high 2D:4D digit ratio (which would indicate excessive prenatal estrogen exposure), and an elevated probability of being left-handed, suggesting that disturbed hemispheric brain lateralization may play a role in paraphilic attractions.

[46] Behavioral explanations propose that paraphilias are conditioned early in life, during an experience that pairs the paraphilic stimulus with intense sexual arousal.

[47] Although paraphilic interests in the general population were believed to be rare, research has shown that fantasies and behaviors related to voyeurism, sadomasochism and couple exhibitionism are not statistically uncommon among adults.

[8] Bestiality has been depicted multiple times in Greek mythology, although the act itself usually involved a deity in zoomorphic form, such as Zeus seducing Europa, Leda and Persephone while disguised as a bull, a swan and a serpent, respectively.

The report, written by Giovanni Pico della Mirandola, described a man who could only be aroused by being beaten with a whip dipped in vinegar.

[8] In American psychiatry, prior to the publication of the DSM-I, paraphilias were classified as cases of "psychopathic personality with pathologic sexuality".

It also provided seven nonexhaustive examples of NOS paraphilias, which besides zoophilia included exhibitionism, necrophilia, partialism, coprophilia, klismaphilia, and urophilia.

[60] The DSM-IV-TR describes paraphilias as "recurrent, intense sexually arousing fantasies, sexual urges or behaviors generally involving nonhuman objects, the suffering or humiliation of oneself or one's partner, or children or other nonconsenting persons that occur over a period of six months" (criterion A), which "cause clinically significant distress or impairment in social, occupational, or other important areas of functioning" (criterion B).

One would ascertain a paraphilia (according to the nature of the urges, fantasies, or behaviors) but diagnose a paraphilic disorder (on the basis of distress and impairment).

"[63] Bioethics professor Alice Dreger interpreted these changes as "a subtle way of saying sexual kinks are basically okay – so okay, the sub-work group doesn't actually bother to define paraphilia.

[65] Linguist Andrew Clinton Hinderliter argued that "including some sexual interests—but not others—in the DSM creates a fundamental asymmetry and communicates a negative value judgment against the sexual interests included," and leaves the paraphilias in a situation similar to ego-dystonic homosexuality, which was removed from the DSM because it was no longer recognized as a mental disorder.

[72] Instead, the goal of therapy is normally to reduce the person's discomfort with their paraphilia and limit the risk of any harmful, anti-social, or criminal behavior.

[72] Cognitive behavioral therapy, at times, can help people with extreme paraphilic disorders develop strategies to avoid acting on their interests.

[72] It is currently the only form of psychotherapy for paraphilic disorders supported by randomized double-blind trials, as opposed to case studies and consensus of expert opinion.

[74] Selective serotonin reuptake inhibitors (SSRIs) have been well received and are considered an important pharmacological treatment of severe paraphilic disorders.

[74] Due to the side effects, the World Federation of Societies of Biological Psychiatry recommends that hormonal treatments only be used when there is a serious risk of sexual violence, or when other methods have failed.