Nathan Denette/CP Ontario Premier Doug Ford speaks to the media during a press conference in downtown Toronto on Dec. 18, 2018.

Those 2015 updates included lessons warning about online bullying and sexting, but opponents, especially social conservatives, objected to parts addressing same-sex relationships and gender identity.

Both the Canadian Civil Liberties Association and the Elementary Teachers' Federation of Ontario allege the Progressive Conservative government's repeal of updates the previous Liberal government made to the curriculum is unconstitutional, saying it puts students at risk.

TORONTO — The Constitution does not set out what sexual health topics must be taught in schools, Ontario government lawyers argue as they ask a court to dismiss a challenge to the province's sex-ed curriculum.

Lawyers for the Progressive Conservative government argue in a document filed ahead of a Wednesday hearing that the Constitution doesn't entrench any particular curriculum and is not a matter of constitutional law.

"The legislature has given to the minister, and not to the courts or the applicants, the responsibility to set educational priorities and direction for all of Ontario's publicly funded schools," the government argues.

Education Minister Lisa Thompson ordered schools to teach a curriculum based on the previous version from 1998 as the government conducted public consultations on sex education.

"This determination should be approached with deference by the court, given the minister's democratic accountability and her greater institutional expertise in matters relating to education," the government argues.

An overwhelming majority of roughly 1,600 submissions on the first day of consultations opposed the repeal of the modernized sex-ed curriculum, but Premier Doug Ford suggested "certain groups" flooded the process in its early stages.

The 1998 curriculum temporarily replaced the updated Liberal document, but it was panned by critics who said it didn't address themes like gender identity, consent and cyber-safety.

The government later announced it had come up with an interim lesson plan that addressed those issues but experts said it contains only passing mention of modern concepts such as the internet and cellphones and largely used the vague language and broad topic outlines used in the 1998 document.

The government argues that if the curriculum prior to 2015 didn't infringe the charter, it can't be unconstitutional to return to it.