R v GK (2001) NSWCCA 413

In this matter Greg Walsh represented the respondent in respect of the submissions of two questions of law to the Court of Criminal Appeal under s5A of the Criminal Appeal Act 1912 (NSW). The questions arose out of the trial of GK on charges of sexual assault involving GK’s step-daughter. At the trial in September 1999, the Crown tried to prove that GK was the father of the complainant’s baby by tendering evidence of DNA testing. Objection was taken to the evidence under s137 of the Evidence Act 1995 (NSW).

Ford DCJ limited admissibility to evidence that the testing did not exclude the possibility of paternity. He refused to allow evidence of likelihood of the percentage of probability of paternity. GK was represented for trial in February 2000 before Moore DCJ and a jury. The Crown again sought to lead evidence of further DNA testing which has been carried out since the first trial. Moore DCJ conducted a voir dire in which experts called by the Crown give evidence about the interpretation of DNA testing.

Moore DCJ held that legal principles required for him “not to disturb exercises of discretion from that which was exercised by His Honour Judge Ford”. He ruled that “there should not be arithmetical figures put before the jury.” The second trial aborted and the third was conducted on the basis of the rulings in the second. The jury finding the Respondent not guilty.

The Court of Criminal Appeal determined the questions as follows:

1. Where a trial judge makes a discretionary ruling on the admissibility of certain evidence, is a trial judge at a subsequent trial following a favour by the first jury to agree on its verdict bound to follow that ruling with respect to the inadmissibility of that same evidence?

No.

2. Was his Honour Judge Moore in error in refusing to admit evidence of the probability, in numerical terms derived from DNA testing that GK was the father of the complainant’s child, on the basis that there was a real risk of unpaired prejudice to the accused?

Yes as paternity index statistics, No as to relative chance of paternity statistics.