In a perfect world there would be no racial or sexual discrimination, no torture, no violence against women, no slavery, no drug trafficking, no corruption, and so on. In the real world they are old scourges of mankind. As such they have special days on the United Nations calendar to focus attention on them. Yesterday was World Aids Day. What sets HIV/Aids apart is that it is a modern scourge, caused by a virus identified only a quarter of a century ago, and not an example of man's inhumanity to man. In a perfect world there would be no unsafe sex, unsafe drug injecting or unsafe blood transfusions; no poverty or ignorance; free condoms for the world's poor, and affordable retroviral drugs for the most impoverished nations; universal anti-HIV/Aids education; and no discrimination against HIV/Aids sufferers. The infection would then be avoidable and more controllable and there would be no need for World Aids Day. Sadly, the real world falls short of all those ideals. As a result there are few days on the UN calendar for which there is such a clear and present justification. Until a vaccine or cure is found, the world is doomed to live with the disease, at unimaginable cost in human life and misery. Microbiologists say it may never be eradicated. The 414 new reported HIV cases in Hong Kong last year, the highest since surveillance began in 1984, could be surpassed this year. Yet Aids is rarely talked about openly in our community. We remain among developed nations that have yet to fully put aside the cultural taboos, denial, stigma and discrimination that hamper the fight against the disease. It is important that we do. We live in the centre of a region where infection rates are rising. For example, mainland health authorities report that the number of HIV-positive gay men in mainland cities has risen sharply in the past three years. The lesson of Africa, the front line of the Aids epidemic, looms large. Conservative ideologies and moralistic approaches have failed with devastating human, social and economic costs. Openness and education in responsible behaviour and potentially life-saving precautions offer the best hope of safeguarding our well-being.