"What we do know is children quite often do not tell about the abuse," she said.
Research had shown most people delayed their reporting until they were adults and only a third would report the abuse during childhood. While there might be a delay, it did not affect the validity of the complaint, Dr Ahmad said.
Studies had shown there were a multitude of reasons why children did not raise the issue of sexual abuse when they were young, which included not being believed, they believe nothing would change, a reluctance to burden others and a fear of loss of control of the shared information.
Children who were "groomed" may also delay reporting. Money, lollies and alcohol were given to the child to develop a relationship. Grooming also involves increased intimate touching to gradually sexualised touching with the child. Research showed abusers typically targeted vulnerable children including those in trouble, passive, lacking in self esteem or confidence.
Defence lawyer Chris Muston put several propositions to Dr Ahmad about memory recall and distorted memories.
She said while some peripheral facts may be incorrect the main trauma would be clear and consistent even after a delayed time.