Last month, actor Michael Douglas gave a frank interview in which he revealed that human papillomavirus (HPV) caused his throat cancer. And, he continued, he got the virus from performing oral sex — specifically, cunnilingus (oral contact with female genitalia). It’s unusual for celebrities to be open about their STD status — and Douglas’ spokesperson has since backpedaled on his comment — so Douglas is to be commended for bringing light to a taboo and little-understood topic. But there were a few things he got wrong, too.

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No matter your gender or sexual orientation, performing unprotected oral sex can increase cancer risk.

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HPV is a common virus that can be spread by most sexual activities — including vaginal, anal, and oral sex, as well as rubbing genitals together. There are many strains of HPV, which come in two main categories: low-risk HPV, which can cause genital warts; and high-risk HPV, which can cause cancers of the cervix, anus, vagina, vulva, penis, mouth, and throat. The majority of HPV-related cancers are caused by two strains of HPV: HPV-16 and HPV-18.

The good news is that there is a vaccine that can protect you from infection by HPV-16 and HPV-18. Furthermore, most people clear an HPV infection within two years. HPV-related throat cancer is rare, affecting just 2.6 out of 100,000 people.

Can oral sex really lead to throat cancer?

Unfortunately, it is absolutely true that oral sex can transmit HPV, and a chronic infection can cause cancer. Oral sex is indeed sex. It’s not “third base,” it’s not “almost sex,” it’s plain old, straight-up sex, carrying with it the potential for both pleasure and disease transmission. Unfortunately, because so many of us have a lax attitude toward it, fewer people take precautions when engaging in oral sex, and are less likely to use condoms or dental dams. Combined with low vaccination rates for HPV in the United States, the virus is even easier to acquire than it needs to be.

Mouth and throat cancers (referred to collectively as oropharyngeal cancers) used to be caused mostly by tobacco, but today, as smoking is becoming less common, an ever-increasing proportion of them are caused by HPV. While only 15 percent of oropharyngeal cancers were caused by HPV 30 years ago, nowadays the virus is behind more than half of them. One estimate states that the number of HPV-positive oropharyngeal cancers will surpass cervical cancers by 2020.

It was recently found that oral HPV is more common in males than in females — and so are HPV-caused oropharyngeal cancers, which strike men at a rate three times higher than they strike women. While oral HPV infection is less common (at any given time, less than 7 percent of adults have oral HPV infections, while 42.5 percent of women have genital HPV infections), the percentage of oropharyngeal cancers caused by HPV is rising, especially in heterosexual men. We don’t know why, but it seems that performing cunnilingus might be riskier than performing fellatio, possibly because HPV passes more easily through the vulva’s thin mucous membranes than through the thicker skin of the penis. (Stats on oral HPV in lesbians are difficult to find, but lesbians can indeed get HPV.)

When HPV causes oropharyngeal cancer, it usually occurs at the base of the tongue, at the back of the throat, in the tonsils, or in the soft palate. Symptoms might include:

• patches (white, red, or both) inside the mouth or on lips
• sores in the oral cavity that don’t heal
• bleeding in the mouth
• difficulty swallowing

Despite the toll that HPV can take on males, boys and men are usually ignored by vaccination campaigns. Gardasil protects against the two strains of HPV that cause 90 percent of genital warts — a condition that affects males and females equally — and two strains of cancer-causing HPV. While the cancer burden currently disproportionately affects females, males can suffer from HPV-related oropharyngeal, anal, and penile cancers. So far, research hasn’t been published on the efficacy of the HPV vaccines against oropharyngeal and penile cancers, but as data emerge, we may very well start to gather evidence of its effectiveness against other forms of cancer.

What did Michael Douglas get wrong?

Unfortunately, Douglas made a couple of other remarks in his interview that aren’t scientifically solid. First, he downplayed the role that smoking might have played in his cancer. And second, he claimed that, while cunnilingus was the cause of his cancer, “cunnilingus is also the best cure.”

Smoking: While tobacco can cause oropharyngeal cancers on its own, it can also increase risk when combined with an oral HPV infection. Anyone with an oral HPV infection can further increase cancer risk by using tobacco. (Poor dental hygiene might also increase risk.) Although people with a healthy immune system will likely clear the virus within two years, smoking interferes with the immune process, allowing HPV infections to linger for a longer time.

The cunnilingus cure?: Perhaps Douglas’ remark that “cunnilingus is … the best cure” for oropharyngeal cancer was just a flippant attempt at humor. However, in case it needs clarifying, we should point out that performing oral sex will not help clear an HPV infection or reduce tumor growth.

If you are concerned you have symptoms of oropharyngeal cancer, Planned Parenthood Arizona can refer you to specialists who can evaluate your mouth and throat. You can also ask a dentist or doctor to perform a physical examination — although not all signs of cancer can be caught by a visual inspection.

Make an appointment at a Planned Parenthood health center to receive education about HPV, as well as the preventive vaccine, Gardasil, which protects against two cancer-causing strains of the virus. While Gardasil has been approved for the prevention of cancers and precancers of the cervix, anus, vulva, and vagina, it so far has not been approved for the prevention of penile or oropharyngeal cancer. However, because HPV can cause cancers in these locations, it seems likely that in the future, independent research will emerge pointing to Gardasil’s efficacy in preventing penile and oropharyngeal cancers as well.

Click here to check out other installments of our monthly STD Awareness series!