TORONTO (Reuters) - Canada’s bestiality law only bans sexual acts that involve penetration, the country’s Supreme Court ruled on Thursday, a blow to advocacy groups who argued animals should be afforded the same protection from exploitation that humans are given.

A view shows the Supreme Court of Canada in Ottawa April 24, 2014. REUTERS/Chris Wattie

Supreme Court judges ruled 6-1 in favor of a man from British Columbia in western Canada convicted for sexual assault and bestiality after he involved the family dog in the abuse of his two stepdaughters.

The man, known only by the initials “D.L.W.” to protect his stepdaughters’ identity, successfully appealed his bestiality conviction in a provincial court, arguing that according to the law, the offense of bestiality requires penetration, which his actions did not involve.

Justice Thomas Cromwell, writing for all concurring judges, said in the decision that penetration has always been required to secure bestiality convictions and courts do not have the power to rule otherwise.

“Any expansion of criminal liability for this offense is within parliament’s exclusive domain,” he wrote.

Justice Rosalie Silberman Abella, the lone dissenter, wrote bestiality is ambiguous under the law, which she says intends for all animal sex acts to be illegal.

A bill that in part seeks to define bestiality as all inter-species sexual activity is before lawmakers, but it is still in its early stages.

Camille Labchuk, executive director of the Animal Justice group, an animal rights group which was allowed to intervene in the case, urged parliament to pass the legislation quickly.

“People who sexually abuse animals are sometimes linked to sexually abusing children as well, as the accused did in this case,” she said. “That’s a really good reason parliament needs to act.”

D.L.W. was originally convicted of 13 offenses involving his stepdaughters, including one charge of bestiality, and is currently serving a 16-year prison sentence.

For a link to the Supreme Court decision, click here