Fantasy refers to the mental image of a person, object, or situation, often but certainly not always involving a sexual component. Fantasies may be based upon past experiences or may be entirely imaginary. Commonly they include a combination of both. It is normal for individuals to fantasize.

Human sexuality is a dimension of social life that is often rich with many different sorts of fantasies. Sexual fantasies often entail mental scenarios involving persons other than one's regular partner and include sexual activities considered culturally inappropriate or unacceptable.

What Triggers Fantasies?
People vary considerably in their ability to fantasize and in their enjoyment of this behavior. Fantasies may supplant reality for some or may serve as a poor substitute of sexual reality for others. Fantasies are often triggered by external stimuli, such as an attractive stranger or an erotic picture, movie, or story.

Researchers have varying views on gender differences in fantasizing. Some argue that males are more prone to fantasize while others assert that fantasy is more common among women. Linda Wolfe studied a sample of 15,000 women ages 18-34, and less than three percent said they never fantasize.

Male Sexual Fantasies
In Western societies, males more often use sexually explicit material as a part of fantasy, whereas females are more likely to rely upon romance stories. Females are more likely to prefer erotica with a "softer," more imaginative side rather than the "harder," more explicit forms preferred by many males.

The male fantasy world relies heavily upon novel experiences filled with culturally-defined beautiful women who are always sexually available and free. Pornographic magazines such as Playboy and Penthouse, as well as a wide array of so-called harder publications (because they depict explicit sex acts), attempt to capitalize upon such fantasies.

Female Sexual Fantasies
Women often base their fantasies upon previous sexual experiences and tend to emphasize romance and intimacy. The onset of the women's liberation movement has created a renaissance in erotic fiction aimed at women by women writers and film makers.

"In Women On Top", Nancy Friday maintains that women have started a sexual revolution for equality and should implement it with a rich fantasy life. In her study of over 10,000 women, Friday noted that in recent years women's fantasies have relied more on active, assertive women giving pleasure, as compared to the fantasies containing more passive women receiving pleasure indicated by prior research. These findings suggest the importance of social environment (e.g., the impact of feminism) on the structuring of fantasy.

People generally fantasize when engaging in autoerotic sex or masturbation. In his research findings, the prominent sexologist Alfred C. Kinsey reported that fantasy accompanied masturbation for the majority (sixty-four percent) of females and virtually all males. About two percent of the women in his study sample reported achieving orgasm by fantasy alone. Older females were more prone to fantasize than younger females. Some people, particularly but not solely those from rural areas, have fantasies about sexual contact with animals.

What Do Fantasies Mean?
Having a fantasy about a particular sexual practice or activity does not mean that a person actually wishes to engage in that behavior or that he/she would enjoy the behavior.

While fantasy may enhance actual sexual practices, it should not be assumed that a fantasized behavior represents an unconscious desire. Thus, some women fantasize about being overpowered or even raped by a man, but this does not mean they actually want to be raped.

Similarly, some men fantasize about multiple sexual partners, but would find it emotionally difficult to maintain several simultaneous relationships.

In recent years, there has been a greater openness about fantasy and a greater recognition of how common this behavior is for both men and women.

While fantasy often is treated as an individual behavior, partners sometimes "act out" shared fantasies to enhance their enjoyment of sex. Computers and the internet have contributed to a new arena of fantasy behavior, with extensive electronic exchange of pornography, interactive role-playing communication, fantasy-constructed chat rooms, and other forms of eroticized and non-eroticized fantasy communication among computer users.

Therapists have found that fantasy can be useful in helping patients overcome sexual problems. With the help of a therapist, the individual may, through fantasy, confront the fearful stages of intimacy and lovemaking and reduce or eliminate those fears and apprehensions.