Final answer:
In a single act of unprotected sex with an infected partner, a teenage girl has the greatest chance of acquiring genital warts, caused by the most common STI in the United States, HPV.
Step-by-step explanation:
According to a study conducted by Glei (1999), in a single act of unprotected sex with an infected partner, a teenage girl has the greatest chance of acquiring genital warts. This is supported by the fact that human papillomavirus (HPV), which causes genital warts, is the most common STI in the United States.
HPV infections cannot be cured, but they can be prevented through vaccination with Gardasil®, especially in females between the ages of 9 and 26 years. Although chlamydia is the most commonly reported bacterial STI, and both gonorrhea and genital herpes are also prevalent, the high rate of HPV infections makes genital warts the most likely outcome from an unprotected encounter with an infected partner.