While these are seemingly simple questions, there hasn't been much research conducted on foot fetishes—or fetishes at all, for that matter. That's why we reached out to Dr. Justin Lehmiller, research fellow at the Kinsey Institute and author Tell Me What You Want. While conducting research for his book, Lehmiller surveyed more than 4,000 Americans about their sexual fantasies. Among other things, he asked about fantasies pertaining to feet and toes. Here's what he learned.

Why do people have foot fetishes?

Fetishes—about feet or something else—are a "multi-sensory experience," Lehmiller says: "Different people might find very different things arousing about their fetish object."

"In the case of feet, it’s more about the visual aspect for some, but for others it may be about sniffing, licking, or otherwise touching feet, including using them during sexual penetration," he says. "People may be interested in any combination of these activities, or any other activity in which feet are involved, including being stepped on or helping a partner take footwear on and off."

How common are foot fetishes?

It's hard to say exactly how common foot fetishes are, Lehmiller says. (According to Psychology Today, they're among the most common sexual fetishes.)

"The best source I can cite would be the data I collected for my book Tell Me What You Want," Lehmiller says. "I found that 14% of my participants reported having had a sexual fantasy before in which feet or toes played a prominent role."

"It’s important to note that just because someone has fantasized about feet before doesn’t necessarily mean that they have a fetish for feet—just that they’ve been turned on by the idea of feet at least once," he adds. "So while about 1 in 7 people reported having had a foot fantasy before, the number who have a true fetish for feet, in the sense of being primarily or only attracted to feet, is likely much smaller than that."

Here's the breakdown of how many people had fantasized about feet before, broken down into different groups:

5% of heterosexual women

18% of heterosexual men

11% of lesbian and bisexual women

21% of gay and bisexual men.

"So men and persons who identify as anything other than heterosexual are more likely to have fantasized about feet," Lehmiller says.

What causes a foot fetish?

People develop fetishes for different reasons, "but they are largely thought to be learned behaviors," Lehmiller says.

"For example, let’s say you have a partner who spontaneously stimulates your genitals with their feet, and this is something you’ve never experienced before," he says. "Let’s also say that you happened to find it very pleasurable and had an intense orgasm. This could create positive reinforcement that would lead you to want to repeat the experience in the future, thereby laying the groundwork for a foot fetish."

What are some of the biggest misconceptions about foot fetishes?

People wrongly assume that having a foot fetish means you have a mental disorder, Lehmiller says. Fetishes can become a problem—like if a person is distressed about their own fetish, or if they're committing crimes in order to fulfill their desires—but for the most part, there's nothing wrong with having very specific turn-ons when it comes to sex.

"Generally speaking, there’s nothing wrong with having a fetish," Lehmiller says. "Fetishes don’t mean you have a mental problem or that you’re unable to establish healthy sexual or romantic relationships."