Montreal's Catholic archdiocese earned itself a scolding from Quebec's education minister on Thursday after it promoted a proposal that parents opposed to the province's new sexual education curriculum could opt out and teach the subject themselves.

Minister Jean-Francois Roberge quickly shot down the idea on Twitter with a reminder that the sex-ed curriculum is mandatory in all but a few circumstances.

"Sexual education: essential learning," the minister wrote.

"The only exemptions granted will be in an exceptional manner for very specific reasons, for example for students who have experienced a significant trauma."

A news release distributed by the archdiocese this week suggested parents can reach an agreement with their children's teachers to teach the subject at home from a manual produced by Rev. Robert Gendreau, director of liturgy services at the archdiocese, and Raouf Ayas, a cardiologist.

"Several parents believe the government imposes sexual education too early, and in a manner that runs counter to their values," read the release sent out by the archdiocese's communications department.

The statement acknowledged the government has offered no opt-out provision, but it suggested parents could get "special permission" to teach the subject at home.

Premier Francois Legault joined Roberge in quashing that notion, asserting the course would be obligatory for all.

"With everything we're living in recent years, it's important that young people understand all the impacts and are able to see how we can evolve in a society between men and women," Legault told reporters in Montreal.

The archdiocese sent out a second message clarifying that it was not involved in producing or distributing the alternative manual, which it described as a "personal initiative" of the authors.

The manual, which is for sale on Amazon, claims to respect the Education Department's directives while guiding parents on how to present the material in accordance with Catholic values.

In its preface, the text says that children between the ages of six and 12 are generally in a period of sexual dormancy and argues the government is introducing sexual material at too young an age.

"It will always be detrimental to the healthy development of the child to force his natural modesty," the authors write.

"Government action in this sense could be considered aggression, whereas that is exactly what it claims to want to prevent."

The government says the information students receive in school will be based on their age and will deal with sexuality, anatomy, body image, sexual assault, love, sexual relations, stereotypes and sexually transmitted infections.

The son of one of the book's authors said the alternative curriculum touches all the same topics but approaches them in "a manner that is respectful of child development and also our world view as faith parents."

As an example, Raymond Ayas said, said the book places more emphasis on the role of love and family in reproduction rather than the simple mechanics of the sexual act.

"Because we believe the family is the basic unit of society, and where does a child come from? It comes from love," he said.

"That was a general sense that had to be reinjected back into the material."

As of Thursday afternoon, the manual occupied the top spot on the French-language best-seller list on Ayas said the buyers include several teachers, who have written to say they'll use it as a tool to help them plan their lessons.