One of the most common sexually transmitted infections is caused by human papillomavirus (HPV). The HPV 16 strain of the virus infection causes cancer to two out of every three people with oral cancer in the United States and the stats are similar for most western nations. Males are twice likely to get infected with HPV than women, claims a new study presented at the annual meeting of the American Association for the Advancement of Science (AAAS) in the US capital on Friday.

The risk of contracting HPV infection is directly proportional to oral sex activity with higher number of partners. Men are at twice higher risk of getting HPV-related cancers compared to women. Most common being mouth and throat cancer among men. Though there are treatment available for HPV infection and a person can be cured within two years from diagnose. However, women in most of the cases survive treatment, possibly due to an immune system response. In case of men, the infection is difficult to clear and in some extreme cases, it leads to cancer.

The study stated that White men in middle age are more vulnerable compared to other races. The cases of oral cancer are on rise in recent years as youth at very young ages are engaging in oral sex in comparison to past generations, according to Gypsyamber D'Souza, who teaches epidemiology at Johns Hopkins University in Baltimore, Maryland. "Our research shows that for men, the number of oral sex partners as that number increases, the risk of an oral HPV infection increases," said D'Souza.

When study team compared the males to females with the same number of sexual partners, men were at higher risk of contracting oral HPV infection. The reason behind this difference is that immune system in women stops an oral HPV infection from developing, while the immune system among most male sufferers of HPV, fails to do so.

A study published in January in the Journal of the American Medical Association (JAMA) claimed that oral sex has been linked to 22% higher risk of head and neck cancer. The US Centers for Disease Control and Prevention (CDC) recommends HPV vaccination for all pre-teen boys and girls so they can be protected against the infection before they become sexually active.