Man found guilty of child sexual abuse after sperm found in nappy

The offences concerned a child who was left at the man's house to be looked after by his mother, with whom he shared the house.

The prosecution alleged DNA found in the two-year-old's nappy closely matched the accused and linked him to the 2013 crimes.

A jury found the man, 37, guilty on Friday of counts one and three on the indictment of sexual intercourse with a child under 10 and an act of indecency in front of the child.

Count two was an alternative charge of an act of indecency, so the jury did not need to consider it once finding him guilty on count one.

In closing submissions on Friday, Crown prosecutor Keegan Lee told the jury they should reject the man's evidence – including his denials. He said the man had inconsistencies in his story from two police interviews to his evidence in court, and had since tried to distance himself from the child.

It was the Crown's position the forensic evidence revealed saliva and sperm in the nappy, and other explanations, such as transferring from another surface, were implausible.

Testing strongly supported that the DNA had come from the accused rather than an unrelated person, Mr Lee said.

Defence barrister Paul Edmonds asked the jury why a guilty man would voluntarily go to the police and give two interviews.

The man had also volunteered his DNA.

"Why on Earth ... would he volunteer his DNA if he was guilty, why would he take that risk?" Mr Edmonds said.

He said the amount of sperm tests found in the nappy was very low, and it was possible the child had touched semen in the house, in the man's bedroom for example, and then touched the nappy.

He said the tests that allegedly showed saliva in the nappy could be false positives. The court had heard expert evidence that what was thought to be saliva could also be urine.

Chief Justice Helen Murrell continued bail on the same conditions.

The case will return to court next week for sentencing.