We all have them at one point or another.

They can be as tame as kissing a crush. Or they can be "hardcore" and totally taboo.

Loving or lurid, sexual fantasies pique a lot of interest and sometimes evoke shame.

Although many Americans consider themselves sexually liberated and uninhibited, many still blush when it comes to this secret aspect of their sexual selves.

So what is the mind’s erotic movie reel concocting that elicits so much guilt? And, can these sexual fantasies actually be more beneficial to your sex life than bad?

The answer to the latter question is yes. Sex educators and therapists are big fans of sexual fantasy.

After all, there are many benefits of fantasizing:

— Erotic fantasy is a great substitute for sex when you can’t actually have sex.

— Fantasy can eroticize safer sex.

— You can fantasize anywhere.

— It’s free.

— It can enable you to overcome sexual anxieties and, in turn, boost your sexual self-confidence.

— It provides you with new ideas for sexual exploration.

Further, in creating visual imagery that turns you on, fantasizing can help you become aroused and reach orgasm. During private time, with or without a partner, this normal, healthy mental stimulation can heighten your sexual experience and pleasure.

Yet, despite all that fantasy has to offer, many people are plagued with great shame and remorse when it comes to fantasies, especially the ones they see as "perverse."

The funny thing is, many people are "thinking off" on the same topics. One major study by London-based psychotherapist Brett Kahr, which involved more than 23,000 sexual fantasies, found the most popular phantasms are those involving bondage, sadomasochism, voyeurism and exhibitionism.

Other research has found that the most common fantasies for men and women involve any combination of third-party sex and using a video camera. Both genders also think about reliving past experiences, engaging in oral sex or about their current partners.

Popular fantasies also include lovemaking positions, being found irresistible, anonymous partners and sex with a new partner.

When it comes to gender differences, our sexual fantasies are more alike than similar. Still, differences do exist.

Male sexual fantasies are more likely to focus on specific sexual acts and sexual organs, and involve more visual content.

The male will think more about his fantasized partner’s responses and physical appearance. Seeing himself as dominant, he views others as the object of his desire. Overall, his fantasies are more frequent, visual, specifically sexual, promiscuous and active.

Women’s sexual fantasies, on the other hand, are more likely to involve familiar partners and to include more description. Their story lines tend to build slowly to explicit activity. These fantasies involve more of a context, setting and feelings associated with the encounter.

With her, fantasies usually are more affectionate and passionate, and she focuses more on her imagined partner’s personal or emotional characteristics. Often the object of desire, her fantasies may involve seeing herself as submissive in a "play with me" kind of way.

What can be most distressing for some individuals is that their fantasies revolve around people other than their actual partner.

If this is your worry, I can provide relief on two fronts. First, such phantasms are extremely prevalent. A Canadian study in 2000 found that 87 percent of male and female participants have had fantasies in the past two months involving someone other than their current partner.

Second, this should not be seen as a sign of disloyalty or dissatisfaction in a relationship. You are not violating your faithfulness by imagining that you are with somebody else.

In fact, fantasy in all of its forms, including those involving imagined or real people, introduces variety and excitement. Both of these are important components in keeping your actual sex life hot.

In addition, many married people will tell you that their ability to fantasize about others is what helps them to remain faithful. It also helps to counter the boredom that can come with a sexually monotonous, long-term relationship.

So embrace your fantasies and reap the benefits. These steamy thoughts help to keep your dopamine levels up, which, in turn, makes you and your partner motivated for more action. This is especially true if you act them out, a topic I’ll leave for a future column ...

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Dr. Yvonne Kristín Fulbright is a sex educator, relationship expert, columnist and founder of Sexuality Source Inc. She is the author of several books including, "Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots."

Click here to read more FOXSexpert columns.