Reuters reports gay males who have had at least four sexual partners are at a risk of catching human papillomavirus (HPV), which can cause genital warts and anal cancer, as well as cervical cancer among women.

In a study, 200 gay men between the ages of 16 to 20 were tested for HPV and genital warts; 11 percent tested positive for two or more forms.

"In this study we found rates of anal infection increased rapidly with increasing numbers of partners with whom they have received anal sex," said they study's senior author Marcus Y. Chen, according to Reuters. "The virus is presumably being transmitted from penis to anus."

The Centers for Disease and Control (CDC) recommends that boys and girls get the HPV vaccination by ages 11 or 12, before they are sexually active. The CDC also states that at least half of sexually active people get HPV at some point in their lives.

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