A coalition of Christian groups is disappointed by a Supreme Court of Canada ruling that will prevent their children from opting out of a controversial religion and ethics course in Quebec.

On Friday, Canada's highest court ruled that the mandatory course does not infringe on the charter rights of a Quebec couple that launched a legal battle to pull their son from class.

The Drummondville, Que. couple in the case believe the course curriculum interferes with their ability to pass on their faith to their children, and violates their freedom of religion.

In its unanimous decision, the Supreme Court disagreed, and issued a verdict that upholds a lower Quebec court decision refusing to grant an exemption to the family's child.

The head of the Catholic Parents Association, Jean Morse-Chevrier, said parents belonging to her group feel let down.

"What we're hoping is that the Quebec minister of education will revisit their attitude towards this course," he said.

Parents Morse-Chevrier works with will start gathering evidence that the course harms their children, in the hopes they can pursue legal action again at a future time, he said.

The parents who launched the case said Friday that the court decision could have serious consequences.

"My son is in fourth grade and he already asks questions about his own religion and I find it sad that it's happening at such a young age," said S.L., the mother who can only be identified by her initials, because of a publication ban.

She and her supporters say the course trivializes faith by treating students to a religious buffet.

"There's a time for everything and I think that teaching about other religions should be done a little later, when the kids are a little older."

S.L. said her family, and other parents may consider another legal challenge.

The family filed a suit against the schoolboard and the Quebec government, but failed to convince a Quebec Superior Court justice to grant the exemptions.

The province's Court of Appeal refused to hear the case. Quebec introduced the ethics and religious culture curriculum to replace the former Protestant and Catholic religious courses for all students except those in Grade 9.

The government billed the course as a way of fostering harmonious relations among students of different backgrounds, and of introducing them to religious practices and traditions from around the world as well as from Quebec.