TORONTO -- Ontario's Liberal government has released a new ad promoting an updated sex-education curriculum that will be in schools when classes resume next week.

The new curriculum has met with some opposition and controversy and has prompted protests by some parents, with some even threatening to pull their kids out of school this year.

The new ad shows young people in a variety of situations: a boy looking at a figure of two grooms atop a wedding cake, a girl examining herself in a full-length mirror, a boy using social media, a girl starting to lift up her shirt and appearing to take a selfie, and a boy leading a nervous-looking girl inside at a house party.

"Our kids have questions," a narrator says as the kids and teens in those scenarios raise their hands. "The sex-ed and health curriculum can help."

The ad stresses that this is the first update to the curriculum in 17 years.

Some parents have raised concerns that some of the material is not age appropriate, with many parents pointing to sections on same-sex relationships, gender identity and masturbation.

Supporters of the curriculum say the opposition is largely founded on misinformation.

Education Minister Liz Sandals said the government's "top priority" is the health and safety of students.

"The Health and Physical Education curriculum was dangerously out of date, last updated in 1998, long before Facebook and Snapchat became part of everyday life," she said in a statement.

"Parents play an integral role in their child's education, and we're launching this campaign so that parents have factual information about what's in the updated curriculum."

Under the changes, Grade 3 students will learn about same-sex relationships, kids in Grades 4 and up will learn more about the dangers of online bullying, while the perils of sexting will come in Grade 7.

Lessons about puberty will move from Grade 5 to Grade 4, while masturbation and "gender expression" are mentioned in the Grade 6 curriculum. Anal sex is part of the Grade 7 curriculum, in the context of choosing to abstain from or delay certain activities in order to avoid sexually transmitted infections.

Premier Kathleen Wynne met in April with a group of parents opposed to the curriculum and said they will just have to "agree to disagree" on it.