In order to determine the relative prevalence of different fetishes, scientists obtained a sample of at least 5000 individuals worldwide, in 2007, from 381 Internet discussion groups. The relative prevalences were estimated based on (a) the number of groups devoted to a particular fetish, (b) the number of individuals participating in the groups and (c) the number of messages exchanged. Of the sampled population, 7 percent were sexually aroused by hair (as opposed to 12 for underwear, but only 4 for genitals, 3 for breasts, 2 for buttocks, and less than one for body hair).

Technically, hair fetishism is called trichophilia, which comes from the Greek ""trica-"" (τρίχα), which means hair, and the suffix ""-philia"" (φιλία), which means love.

Research has shown that paraphilias are rarely observed in women. However, there have been some studies on females with paraphilias. Sexual masochism has been found to be the most commonly observed paraphilia in women, with approximately 1 in 20 cases of sexual masochism being female.

Many acknowledge the scarcity of research on female paraphilias. The majority of paraphilia studies are conducted on people who have been convicted of sex crimes. Since the number of male convicted sex offenders far exceeds the number of female convicted sex offenders, research on paraphilic behavior in women is consequently lacking. Some researchers argue that an underrepresentation exists concerning pedophilia in females. Due to the low number of women in studies on pedophilia, most studies are based from "exclusively male samples". This likely underrepresentation may also be attributable to a "societal tendency to dismiss the negative impact of sexual relationships between young boys and adult women". Michele Elliott has done extensive research on child sexual abuse committed by females, publishing the book "Female Sexual Abuse of Children: The Last Taboo" in an attempt to challenge the gender-biased discourse surrounding sex crimes. John Hunsley states that physiological limitations in the study of female sexuality must also be acknowledged when considering research on paraphilias. He states that while a man's sexual arousal can be directly measured from his erection (see penile plethysmograph), a woman's sexual arousal cannot be measured as clearly (see vaginal photoplethysmograph), and therefore research concerning female sexuality is rarely as conclusive as research on men.

The prevalence of fetishism is not known with certainty. The majority of fetishists are male. In a 2011 study, 30% of men reported fetishistic fantasies, and 24.5% had engaged in fetishistic acts. Of those reporting fantasies, 45% said the fetish was intensely sexually arousing. In a 2014 study, 26.3% of women and 27.8% of men acknowledged any fantasies about "having sex with a fetish or non-sexual object". A content analysis of the sample's favorite fantasies found that 14% of the male fantasies involved fetishism (including feet, nonsexual objects, and specific clothing), and 4.7% focused on a specific body part other than feet. None of the women's favorite fantasies had fetishistic themes. Another study found that 28% of men and 11% of women reported fetishistic arousal (including feet, fabrics, and objects "like shoes, gloves, or plush toys"). 18% of men in a 1980 study reported fetishistic fantasies.

Fetishism to the extent that it becomes a disorder appears to be rare, with less than 1% of general psychiatric patients presenting fetishism as their primary problem. It is also uncommon in forensic populations.

Fetishism usually becomes evident during puberty, and may develop prior to that. No cause for fetishism has been conclusively established.

Some explanations invoke classical conditioning. In several experiments, men have been conditioned to show arousal to stimuli like boots, geometric shapes or penny jars by pairing these cues with conventional erotica. According to John Bancroft, conditioning alone cannot explain fetishism, because it does not result in fetishism for most people. He suggests that conditioning combines with some other factor, such as an abnormality in the sexual learning process.

Theories of sexual imprinting propose that humans learn to recognize sexually desirable features and activities during childhood. Fetishism could result when a child is imprinted with an overly narrow or "incorrect" concept of a sex object. Imprinting seems to occur during the child's earliest experiences with arousal and desire, and is based on "an egocentric evaluation of salient reward- or pleasure-related characteristics that differ from one individual to another."

Neurological differences may play a role in some cases. Vilayanur S. Ramachandran observed that the region processing sensory input from the feet lies immediately next to the region processing genital stimulation, and suggested an accidental link between these regions could explain the prevalence of foot fetishism. In one unusual case, an anterior temporal lobectomy relieved an epileptic man's fetish for safety pins.

Various explanations have been put forth for the rarity of female fetishists. Most fetishes are visual in nature, and males are thought to be more sexually sensitive to visual stimuli. Roy Baumeister suggests that male sexuality is unchangeable, except for a brief period in childhood during which fetishism could become established, while female sexuality is fluid throughout life.

Diaper fetishists and diaper lovers (DLs) are often associated with adult babies, as both wear diapers, but the former do not engage in childlike behavior, while that is the distinguishing characteristic of adult babies (ABs). The majority of diaper lovers do not engage in any kind of infantile activity and are only interested in diapers. However, in certain individuals it is possible for an overlap to occur, as one can view themselves as neither exclusively an adult baby nor a diaper lover. Hence adult babies and diaper lovers collectively refer to themselves as AB/DLs. Diapers and rubber pants with "baby" prints are sold in adult sizes.

As a paraphilia, breast fetishism (also known as mastofact, breast partialism, or mazophilia) is a highly atypical sexual interest focused on female breasts (see partialism). The term "breast fetishism" is also used in the non-paraphilic sense, to refer to cultural attention to female breasts and the sexuality they represent, with debate existing as to whether the modern widespread fascination with breasts among heterosexual males in western societies is a sexual fetish.

In 2007, a study was conducted by the University of Bologna on around 5000 fetishist participants to see the prevalence of fetishes. The study analyzed the content inside online fetish communities and found only 669 participants referring to nails, an extension of hand fetishism. This did not refer to fingernails specifically, and the amount of 669 was less than 1% of the participants.

Armpit fetishism (also known as "maschalagnia") is a partialism in which an individual is sexually attracted to armpits - something which may lead to axillism, or armpit intercourse (sexual activity with one or both armpits).

Transvestism is the practice of dressing and acting in a style or manner traditionally associated with the opposite sex. In some cultures, transvestism is practiced for religious, traditional or ceremonial reasons.

Hand fetishism or hand partialism or also Quirofilia is the sexual fetish for hands. This may include the sexual attraction to a specific area such as the fingers, palm or nails, or the attraction to a specific action performed by the hands; which may otherwise be considered non-sexual—such as washing or drying dishes. This fetish may manifest itself as a desire to experience physical interaction, or as a source of sexual fantasy.

Hand fetishism is recognized by the porn industry; however, it is one of the least common fetishes, despite foot fetishism being the most common.

Hand fetishism is usually based in the biological indication that a partner is healthy and a good potential mate.

In order to determine the relative prevalences of different types of fetishes, scientists obtained a sample of at least 5000 individuals worldwide from 381 Internet discussion groups. The relative prevalences were estimated based on (a) the number of groups devoted to a particular fetish, (b) the number of individuals participating in the groups and (c) the number of messages exchanged. Using these measures, feet and shoes were found to be the most common target of preferences. This is consistent with an analysis of millions of search queries by users from the USA that were accidentally released during the AOL search data scandal. Sixty-four (64) percent of the sampled population that had a preference for an object associated with the body had a preference for shoes, boots, and other footwear.

Diaper fetishism, nappy fetishism or diaperism, is a type of garment fetish or paraphilic infantilism. A person with a diaper fetish derives pleasure from the diaper and/or use of it. Being forced to wear diapers as a form of humiliation is sometimes a behavior encountered in sexual masochism.

It is important to note that the diaper fetish community actively opposes and condemns child molesters. Both men and women can practice diaper fetishes, both inside and outside a relationship. As of September 2015, Huffington Post Arts & Culture published an interview on diaper fetishes that was widely regarded as informative within the community. While this clothing fetish is obscure, diaper fetishists engage in the behavior privately or with a partner who shares a mutual interest in the fetish.

Underwear fetishism is a sexual fetishism relating to undergarments, and refers to preoccupation with the sexual excitement of certain types of underwear, including panties, stockings, pantyhose, bras, or other items. Some people experience sexual excitement from wearing, while others get their excitement when observing or handling the underwear worn by another, or watching somebody putting underwear on/taking it off. Some may steal used underwear to get satisfaction. Not only does this include physical contact with the garment(s), or their wearers, but also includes arousal by printed or electronic image with depictions of underwear.

Underwear fetishism is not considered as paraphilia unless it causes distress or serious problems for the person or those associated with them.

The natural body smell is a powerful force in sexual attraction, and can be focused by the strong pungent odor of the armpit: Alex Comfort considered that for a woman to shave her armpits was “simply ignorant vandalism”, obliterating a powerful sexual tool, and praised the French for greater sexual awareness than American deodorant culture in this regard.

A woman's armpits, armpit hair, and secretions can be seen as essential components of her femininity, whether this is positively or negatively valued. Havelock Ellis found evidence that (in a non-sexual context) smelling one's own armpit could act as a temporary energy boost.

In the United States, following a series of landmark cases in the Supreme Court of the United States, persons diagnosed with paraphilias, particularly pedophilia ("Kansas v. Hendricks", 1997) and exhibitionism ("Kansas v. Crane", 2002), with a history of anti-social behavior and related criminal history, can be held indefinitely in civil confinement under various state legislation generically known as sexually violent predator laws and the federal Adam Walsh Act ("United States v. Comstock", 2010).

Boot fetishism is a sexual fetish focused on boots. Boots have become the object of sexual attraction amounting to fetishism for some people and they have become a standard accessory in BDSM scenes (where leather, latex and PVC boots are favoured) and a fashion accessory in music videos. Boots are seen as perhaps the most fetishistic of all footwear and boots may be the most popular fetish clothing attire.

Some people experience sexual excitement from the look or feel of a women's bra. The attraction may be to the look or feel of the material, such as lace, or how it looks on a person. Some people get excitement from removing a bra.

Transvestic fetishism is a psychiatric diagnosis applied to those who are thought to have an excessive sexual or erotic interest in cross-dressing; this interest is often expressed in autoerotic behavior. It differs from cross-dressing for entertainment or other purposes that do not involve sexual arousal, and is categorized as a paraphilia in the Diagnostic and Statistical Manual of the American Psychiatric Association. (Sexual arousal in response to donning sex-typical clothing is homeovestism.)

Robot fetishism (also ASFR or technosexuality) is a fetishistic attraction to humanoid robots; also to people acting like robots or people dressed in robot costumes. A less common fantasy involves transformation into a robot. In these ways it is similar to agalmatophilia, which involves attraction to or transformation into statues or mannequins.

Robot fetishism can be viewed as a form of erotic anthropomorphism. When transformation or roleplaying is involved it can be thought of as a form of erotic objectification.

Mysophilia relates to soiled or dirty material or people. Mysophiliacs may find dirt, soiled underwear, feces, or vomit to be sexually arousing.

It is possible for people with mysophilia to be aroused by unclean locales, such as an alleyway, or a dirty room/bathroom; wearing the same clothing for many days at a time; or not bathing, from mere days to several weeks.

Psychosexual disorders can vary greatly in severity and treatability. Medical professionals and licensed therapists are necessary in diagnosis and treatment plans. Treatment can vary from therapy to prescription medication. Sex therapy, behavioral therapy, and group therapy may be helpful to those suffering distress from sexual dysfunction. More serious sexual perversions may be treated with androgen blockers or selective serotonin reuptake inhibitors (SSRIs) to help restore hormonal and neurochemical balances.

Some researchers have hypothesized that foot fetishism increases as a response to epidemics of sexually transmitted diseases. In one study, conducted by Dr. A James Giannini at Ohio State University an increased interest in feet as sexual objects was observed during the great gonorrhea epidemic of twelfth-century Europe, and the syphilis epidemics of the 16th and 19th centuries in Europe. In the same study, the frequency of foot-fetish depictions in pornographic literature was measured over a 30-year interval. An exponential increase was noted during the period of the current AIDS epidemic. In these cases, sexual foot play was viewed as a safe-sex alternative. However, the researchers noted that these epidemics overlapped periods of relative female emancipation. Sexual focus on female feet was also hypothesized to have been a reflection of a more dominant posture of the woman in sexual-social relations. (The first surviving mention of foot fetish is by Bertold of Regensburg in 1220.)

Gender identity is a concept, specifically psychological, that refers to one's sense of being a male or female in regards to sexual orientation. Individuals who are diagnosed with gender identity disorder are classified as being dissatisfied with their anatomically determined gender.

Shoe fetishism is the attribution of attractive sexual qualities to shoes or other footwear as a matter of sexual preference, or an alternative or complement to a relationship with a partner. It has also been known as retifism, after the French novelist Nicolas-Edme Rétif (October 23, 1734–February 2, 1806), also known as Rétif de la Bretonne. Individuals with shoe fetishism can be erotically interested in women's shoes. Although shoes may appear to carry sexual connotations in mainstream culture (for example, women's shoes are commonly sold as being "sexy") this opinion refers to an ethnographic or cultural context, and is likely not intended to be taken literally. Another fetishism, which sometimes is seen as related to shoe fetishism, is boot fetishism.