TORONTO -- Ontario's revised sex education curriculum will teach Grade 1 students about proper names for body parts and how to understand non-verbal signals like facial expressions and tone of voice.

Details of the first update to the province's health and physical education curriculum since 1998 were released by Education Minister Liz Sandals this morning.

Grade 2 students will learn about the stages of development and related bodily changes along with the concept that "no means no," as well as some elements of verbal and physical violence.

By Grade 3, students will lean about same sex relationships, while lessons about changes associated with puberty will move from Grade 5 to Grade 4.

Students in Grade 6 will learn about masturbation and "gender expression," while kids in Grades 7 and 8 will discuss contraception, anal and oral sex, preventing pregnancy and sexually transmitted infections.

The changes are contained in a 240-page health and physical education curriculum for Grades 1 to 8 and a 218-page covering Grades 9 to 12.

The Liberal government backed away from an attempted update of the sex ed curriculum in 2010 after protests by some religious groups.

But Premier Kathleen Wynne has vowed that the updated curriculum will be in place for the start of the school year in September.

The Opposition has complained the government did not consult enough parents before introducing the revised sex ed curriculum, which Wynne has said will not be changed before being implemented.