China is on the verge of an Aids epidemic, with an estimated one million people affected and the United Nations forecasting the number could be 10 times higher by the end of the decade. Yet, police have arrested the country's best-known Aids activist, Wan Yanhai, a man dedicated to increasing awareness of the incurable killer disease. The charge was theft of state secrets, a tactic increasingly used by the mainland to silence people campaigning for causes. Dr Wan's secrets appear to be no more than readily available HIV/Aids statistics posted on his Web site. His arrest followed years of intimidation. He lost his Health Department job in 1994, while an organisation he set up to increase HIV/Aids awareness was shut down and he was constantly shadowed by police. The Shanghai-trained doctor has not made political statements. Instead, he has highlighted areas where officials are showing their ignorance of HIV/Aids. He has accused Henan province officials of covering up a blood contamination scandal which he claims could decimate the population but is being ignored. His claims are denied by authorities. Dr Wan is pro-gay and lesbian rights. He disappeared on August 24 after a film festival at a gay bar in Beijing. The issues Dr Wan represents cannot be suppressed by official denial, ignorance or a ham-fisted approach. They are realities of the modern world, which China is trying to join. People like Dr Wan are a vital and valued part of that world. Without them, governments would become complacent and problems such as HIV/Aids would spiral beyond control. By locking up Dr Wan and silencing him, Beijing is ignoring reality. Doing so can only be harmful to China's society.