The Supreme Court of Canada will explain Friday why it threw out sexual assault charges against a woman who had sex with the 14-year-old friend of her son.

In May, justices ruled that Saskatchewan resident Barbara George, who was 35 at the time of the sexual encounter, should not face a new trial for sexual interference and sexual assault. It will present written reasons for that decision.

The crux of the case is around age of consent, and a section of the Criminal Code that requires an adult to take "reasonable steps" to determine the age of a person before engaging in sex with them.

George was acquitted of the charges because the trial judge found the sexual activity was "factually consensual" — that she honestly believed the boy was at least 16, and there was reasonable doubt she had not taken all reasonable steps to determine the age of "C.D.," whose full name is protected by a publication ban.

He was attending a party at her home the night of the encounter.

According to documents filed by the appellant with the Supreme Court, George assumed C.D. was over the age of 16 because he had facial hair, a mature demeanour and apparent sexual experience. He also smoked and took care of his younger siblings.

According to the documents, George did not realize how old he was until several months later, when she applied to become an RCMP officer. One of the questions on the questionnaire asked if she had ever had sexual activity with someone under 16.

RCMP application leads to charges

After checking with her son about the age of C.D., she answered the form in the affirmative.

That led to an RCMP investigation and subsequent charges laid against her.

George was acquitted at trial. While the judge said she exhibited an "appalling lack of judgment" by talking to the complainant in her bedroom for several hours that night, there was not enough evidence to show she deliberately broke the law.

The Saskatchewan Court of Appeal, in a majority decision, allowed the Crown's subsequent appeal, sending the matter to the country's highest court.

"This case involves a 35-year-old woman who was the sole parent and adult at a high school party when she had sexual intercourse with a boy who was half her age and young enough to be her teenage son," reads a court document filed by the respondent, the Attorney General of Saskatchewan.

"Despite all of that, she took no steps to ascertain the complainant's age before she had sex with him. In fact, she did not turn her mind to the issue of the complainant's age at all until months later."

In 2008, the Conservative government led by Stephen Harper raised the legal age of consent in Canada from 14 to 16, the first change to the law since 1892.

Age of consent

The Criminal Code amendment allowed for "close in age" or "peer group" exceptions. That means a 14- or 15-year-old can consent as long as the partner is less than five years older, and a 12- or 13-year-old can consent if the partner is less than two years older.

The age of consent remained 18 if the sexual activity involves someone in a position of authority, trust or dependency, or involves exploitation such as pornography or prostitution.

Monique St. Germain, general counsel for the Canadian Centre for Child Protection, said it would be a big problem if the key message from the courts is that if someone looks and acts 16, it's OK to have sex with them.

One would have thought, at the very least, a question should have been asked in terms of age before engaging in sexual activity. - Monique St. Germain, Canadian Centre for the Protection of Children

"What that would mean is that children under 16 would be far less protected from the very harms that Parliament intended that they be protected from," she said.

"One would have thought, at the very least, a question should have been asked in terms of age before engaging in sexual activity."

St. Germain said there is a lack of understanding about the social and psychological development of children, especially boys.

"There is a societal perception that teenage boys engaging in sex with older women is not harmful, and our agency would say that's not the case," she said.

Justin Trottier, executive director of the Canadian Association for Equality (CAFE), would not speculate on whether the outcome might be different if the accused were a man and the victim a girl. But he does believe the criminal justice system has an inherent bias against males in some cases.

Trottier, whose group has stirred controversy for its campaign to raise awareness about domestic violence against men, said when a woman is accused of a sexual offence against a boy, the assumption is that the boy got lucky, he wanted it, he must have been sexually aggressive or that it didn't cause him any harm.

"These are all myths. Boys can be sexually abused, and it certainly does harm them to the same extent as it does girls who are sexually abused," he said.

Relying on facial hair, the fact the complainant smoked or seemed familiar with sex should not be legal grounds for assuming age of consent, he said.