But even that taboo may soon be broken.

ECONOMIST: Big media and the internet

But he adds that the subject is often avoided, and even treated as taboo.

BBC: Brazilian family firms reveal tips for success

As Blairite ministers acknowledge, raising the state-pension age had been taboo even though it was originally set at 65 in 1925, when pensioner life expectancy was much lower.

ECONOMIST: Reforming pensions

Politicians' private lives are largely taboo, even in countries with lively tabloids such as Poland.

ECONOMIST: Life in the global gutter

Even acknowledging profitability is taboo at many facilities.

FORBES

Even acknowledging profitability is taboo.

FORBES: OutFront

Today, the world has been turned on its head to the point where even asking fundamental questions about PLO compliance is taboo.

CENTERFORSECURITYPOLICY: Center For Security Policy

But such is the taboo that almost no-one wants to comment or even to acknowledge that they've read it.

BBC: Gay Afghan defies tradition to expose identity

Analysts say the case shows how much homosexuality is still a taboo in Egypt, where many people are not prepared to even acknowledge it exists.

BBC: 'Extremist' gay trial opens in Egypt

But even love matches can't be openly consummated before marriage, thanks to the taboo against premarital sex.

WSJ: India Needs a Sexual Revolution

Community workers say that debt is a taboo topic for elderly people, and they will keep their money problems secret even from their closest loved ones.

BBC: NEWS | Business | Britain's streets of debt: Easy prey