The Elementary Teachers' Federation of Ontario is taking legal action against the PC government's decision to replace Ontario's modern, 2015 sex-education curriculum with a version that pre-dates same-sex marriage, smartphones and social media.

They also want a judge to get rid of Doug Ford's so-called "snitch line;" a phone number which parents are encouraged to call to report teachers who refuse to go back to 1998.

"The Ford government has thrown the system into uncertainty," said EFTO president Sam Hammond at a press conference on Tuesday, the first day of school for most students in the province. 

"The actions of the government to rescind the 2015 curriculum undermines the very safety and well-being of Ontario students and families."

The union, which represents just under 80,000 elementary school teachers in Ontario, filed a notice of application for judicial review to the Ontario Superior Court of Justice

They are seeking both an injunction to keep the Liberal government's 2015 curriculum in place, and to squash the government's anonymous parent reporting line.

"The purpose and effect of creating the Reporting Line was to intimidate teachers from engaging in expressive activity related to teaching topics included in the New Curriculum," reads the court filing.

"To keep them from abiding by their professional and ethical responsibility as members of the teaching profession, and to prevent them from providing pupils with information critical to protecting their safety, bodily integrity, emotional wellbeing and equality."

By mounting this legal challenge, Ontario's teachers join Tesla, the City of Toronto, and the Canadian Civil Liberties Association in the growing list of organizations taking legal action against the provincial government.