Jury retires in child manslaughter trial

A Sydney jury has begun deliberating in the trial of three relatives charged over the death of a diabetic six-year-old boy.

The boy's mother, father and grandmother have all pleaded not guilty to the manslaughter of the boy in Sydney in April 2015.

The jury in their NSW District Court trial was told the boy's last insulin injection to treat his type 1 diabetes came on the first day of a week-long "radical" Chinese slapping and stretching therapy workshop.

The Crown contends all three accused breached the duty of care they owed the child through gross negligence.

The mother and grandmother argued they thought a practitioner involved in the workshop was a doctor and therefore didn't seek medical treatment or inject insulin.

The father's lawyer asked the jury to consider how much he knew about his son's condition and whether a duty-of-care breach amounted to gross criminal negligence.