I received an email from Yale University this morning. It is looking for volunteer English speakers to teach English in China's Hunan province for a year. As great as the programs goes, I don't quite understand one thing in the ad: Why does STD free needs to be specifically brought up? Are these volunteers would be involved in some activities that could spread STD? Or the organization deprives the right for STD carriers of volunteering? Any brilliant thought? Here is the ad:

“WorldTeach volunteers in China teach in secondary schools in Hunan Province. The program is designed to bring native English speakers to teach students at all socioeconomic levels, as currently in China the upper classes have more opportunities to learn from native speakers.  Your role will be to build students' confidence in English through creative, orally-focused English lessons. 

Volunteers must be native English speakers and have a bachelor's degree. Our partners in China also require that volunteers be under the age of 65 and free of sexually-transmitted infections. Successful volunteers will be flexible, mature, and have a genuine interest in teaching. Chinese language or teaching qualifications are not required, although prior experience will strengthen your application.”