Almost 60 per cent of people who experienced childhood rape were abused before they turned 12, according to statistics released by the State's rape crisis centres.
The 2006 statistics from the Rape Crisis Network Ireland, which are to be released today, show that the youngest victims of rape are also more likely to be abused into adulthood.
"A child, sexually abused within the family, continues to experience a particularly high risk of sexual violence and isolation into adulthood," the network said in a statement.
Fiona Neary, executive director of the network, said that Ireland's culture might play some part in the silence that followed child abuse within the family.
"While the reasons why those sexually abused within the family find it so difficult to tell anyone are complex, these findings challenge Irish society to examine how our attitudes to the family may add to the burden of silence a victim of sexual violence carries in Irish society."
The network's 14 Irish rape crisis centres contributed to the statistics. Of those who came to the centres seeking help, 87 per cent were women and 13 per cent were men.
The most common age for people to seek help was in their 30s, with younger people more likely to seek help than older people.
The perpetrators were nearly always men (97 per cent) and in two-thirds of cases, the survivors of adult sexual violence knew the perpetrator.
Eighty-four per cent of survivors reported one episode of sexual violence, although 10 per cent of those single episodes involved multiple attackers.
The network said that 47 pregnancies after rape were recorded in 2006, and just 14 per cent of people who visited rape crisis centres reported their attack to the Garda.
The network also said that it was becoming more common for young people to report rapes or sexual violence.
"There may be a cultural change breaking some of the silences around sexual violence," the network said in a statement.