A group of families is launching a human rights challenge to the Ontario government's decision to repeal and replace the province's modernized sex-education curriculum.

The Progressive Conservatives have said teachers will use a 1998 version of the curriculum this fall as the government conducts consultations to create a new lesson plan.

Lawyers representing the six families in the case say the decision to reinstate a curriculum that makes no reference to the rights of LGBTQ students goes against the province's human rights code.

The lead applicant in the case is an 11-year-old transgender student due to start Grade Six in September.

Lawyers say the modernized curriculum, which addressed issues of sexuality and gender, made students feel safer in school and created a more informed and inclusive climate by educating teachers and students on important issues.

Scrapping that curriculum, introduced by the Liberal government in 2015, was one of Premier Doug Ford's main campaign promises during the spring election campaign.