There are more than 13 million Aids orphans worldwide, according to a report by aid agencies. That number is projected to double by 2010.

At the world Aids conference in Barcelona, there is a hope that these figures will finally force governments to address a problem they have so far largely ignored.

In many parts of the world when one or both parents die from Aids the stigma of the disease is such that those left behind are tainted.

Many governments have chosen to ignore the issue

Whether or not the children themselves are infected, they become outcasts.

Many are shunned by their extended family and forced out of their communities. They stop attending school.

Education

Without education it is harder to find a job and earn the money they need to keep themselves and their siblings.

Many become angry and disenfranchised. Large numbers of these children growing up on the margins of society have the potential to destabilise what are often fragile democracies struggling to cope with the poverty of their populations.

The reality is there have always been children in developing countries who are forced to eke out an existence on the streets because of their family's extreme poverty, the death of a parent, or other social problems.

But many governments have chosen to ignore the issue.

In many places authorities turn a blind eye to physical and sexual abuse.

In the worst affected countries in Africa one in five children will have lost one or both parents

It has taken years for the world community to accept the problem of commercial sexual exploitation of these children.

Vulnerable group

While the numbers were relatively small it was easy for governments to ignore this vulnerable group and concentrate their efforts on what they regarded as more pressing concerns.

Well now some are arguing the projections for the huge growth in the number of AIDS orphans might change that.

In the worst affected countries in Africa one in five children will have lost one or both parents, by the end of the decade .

The scale of the economic and social problems that it will produce will mean it will no longer be possible to ignore it.

The devastating impact of Aids on individual communities, the argument goes, may turn out to be the strongest driver to ensuring governments put money and effort into some of the many social problems that either contribute to the spread of the disease or exacerbate its effects.

It is optimistic. But it is one of the few glimmers of hope.

Experience in Uganda, where they have at last succeeded in getting the epidemic under control, shows that even as the number of new HIV infections stabilises, the number of Aids orphans continues to grow.

The best guess is that it will be 10 years before it starts to fall.

That makes it the worst kind of problem to try to tackle - one where inordinate amounts of effort will be required with little chance of any kind of success for years to come.

But the alternative, the experts warn, will be a disaster most of the worst affected countries are ill equipped to deal with.