Their customer demographic is also concerning. A recent study of prostitution users showed that their main clients were middle-class men under the age of 35. Men with the highest incomes were considerably more likely to have bought sex than those less well-off (6) . In this manner, commercial sex workers may transmit HIV to their married clients, who will then transfer it to their families. Another factor compounding prostitution usage is the traditional social preference for male children, which became particularly acute following China's one-child policy (10) . There is now an increasing demographic trend for males to outnumber females, with the rate currently believed to be about 120 males for every 100 females (18) . This situation has resulted in less available women for sexually active males, which in turn, encourages or even necessitates prostitution usage. The problem may not be temporary either. From current figures it is anticipated that, over the next decade, around 10 to 15 million young Chinese men will have zero future prospects for marriage. This large demographic of unmarried men may be destined to find no sexual outlet during their lives other than commercial prostitution (10).