When is a particular practice cultural and when is it just something that people have got used to?
Does "culture" justify male promiscuity? Domestic violence? Female genital mutilation?
Is culture the last taboo?
Although we've long known that some cultural practices increase people's risk of HIV infection, governments and aid agencies have often lacked the stomach to take on local custodians of tradition and culture. Women, in particular, have paid the price. Socially accepted norms labelled as "cultural" have violated their human rights, prevented them from achieving economic independence and minimised their control in sexual relationships.
UNAIDS has decided that anything is fair game when it comes to the battle against HIV and AIDS. The agency's recently released 2008 report on the global AIDS epidemic devotes an entire chapter to "Addressing societal causes of HIV risk and vulnerability".
Elizabeth Mataka, the UN's special envoy on AIDS, has made the championing of women's rights a focus of her tenure. After working in the AIDS sector in her home country of Zambia for the past 20 years, she has had ample opportunity to see how social norms like women's lack of property rights have made them susceptible to HIV.
Speaking at the launch of the report in Johannesburg this week she told the story of a woman who was evicted from her home after her husband died from an AIDS-related illness. She ended up sleeping at a bus station where she was sexually abused.
"Culture is a dynamic organism, it's not static, but more often than not people hide behind it," Mataka said. "I think the time has come for us to say, yes, culture is what defines us, but if culture is killing us we need to be bold enough to say that."