TORONTO -- Ontario kids as young as six will learn about consent while eight-year-olds will be taught about same-sex relationships under a revamped sex-education curriculum the province released Monday.

The document -- last updated in 1998 before smartphones were invented --  brings Ontario in line with other provinces, Education Minister Liz Sandals said in a news conference. Some of the changes, she suggested, may even place Ontario ahead of the pack.

"I think that on having a very explicit conversation about consent -- what does consent mean and what do healthy relationships look like -- I think in that piece we may become the leader," she said.

Grade 1 students will learn how to understand non-verbal signals like facial expressions and tone of voice, as well as the proper names for body parts, which was already in the old curriculum.

Sandals said she knows some parents think that's too early for such discussions, but she doesn't think very many will pull their kids out of class.

"Given that we haven't had hoards of people withdrawing from the public education system given what's already in the curriculum, to be perfectly honest, I don't anticipate that affect now," she said.

Other changes include students in Grade 2 will learn about the stages of development and related bodily changes along with the concept that "no means no."

By Grade 3, students will learn about same-sex relationships, which Kathleen Wynne, the first openly gay premier, said would help kids with two moms or two dads feel their families are just like everyone else's.

"It's not about explicit information except that it needs to be about kids feeling safe, feeling protected, feeling like they belong," Wynne said.

Children in Grades 4 and up will learn more about the dangers of online bullying and of posting or sharing sexual images, while specific lessons on the dangers of sexting will come in Grade 7.

One change in the new curriculum will be lessons about puberty will move from Grade 5 to Grade 4.

"We dropped it a grade because what we've seen from public health data is that the age of puberty has been constantly dropping," said Sandals.

Students in Grade 6 will be taught 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.

Grade 8 students will also be taught there are six genders: male, female, two-spirited, transgender, transsexual, intersex.

The Liberal government backed away from an attempted update of the sex ed curriculum in 2010 after protests by some religious leaders, including Charles McVety, president of Canada Christian College.

McVety said Monday that his "number 1 concern" in the revised curriculum is the teaching of gender identify.

"To teach children from a very young age that they may not be the gender of their body and that there may be six genders, this is what they mean by reshaping and reforming the way we think as a culture," McVety said. "I don't think that's why we send our children to school."

Sandals insisted the updated curriculum will be in place for the start of classes in September, regardless of any protests, and said Roman Catholic schools must also implement the new policy.

The Progressive Conservatives said the government should be open to making more changes to the curriculum once parents have had a look at it.

"They have a duty to listen to parents," said interim PC Leader Jim Wilson. "This isn't a law that we get to vote on here, this is a regulation, so it's really important that you speak up if you have concerns."

The Ontario Physical and Health Education Association called the curriculum update long overdue and cautioned critics against overreacting.

"The Opposition and everyone in the public and the media especially need to understand the content of the curriculum before we start forming opinions, before we start fear mongering," said executive director Chris Markham.

Planned Parenthood praised the inclusion of consent in the revised curriculum, the lessons about online activities, as well as the decision to teach about puberty at an earlier grade.

"This is the curriculum catching up with where youth, parents and teachers are already at," said spokeswoman Lauren Dobson-Hughes. "And it's giving them the tools finally they need to understand some pretty complex issues in their lives."