A protest against the province's sex-ed curriculum was held outside Thorncliffe Park Public school in East York Tuesday.

Ryan Bird, a spokesman for the Toronto District School Board, estimated that nearly 700 students, about half the school population, did not come to school as a result of the rally.

On Saturday, Premier Kathleen Wynne's visit to a back-to-school fair in Thorncliffe Park was met with some vocal opposition over the sex-education curriculum.

Thorncliffe Park has a large immigrant population. Immigrants with conservative or strong faith-based backgrounds have been among the most vocal critics of the province's new plan.

Complaints from parents have ranged from a lack of consultation with them, to lessons not being age-appropriate, to not wanting their kids to be taught about same-sex relationships and different gender identities.

Premier Kathleen Wynne said in addition to thousands of school council chairs, 70 health organizations and parent groups were consulted in crafting the new curriculum, which had not been updated since 1998.

"This is the most widely consulted upon curriculum in the history of the province," she said Tuesday.

"When we write curriculum … on geography or social studies or mathematics, that kind of consultation does not happen because that's not how curriculum has been historically written in the province.

"We felt there was a need to have a broader consultation with parents on this curriculum."

Sandals warns of 'misinformation'

Progressive Conservative MPP Monte McNaughton, who has been a staunch opponent of the curriculum, is urging Wynne to shelve the document and start over by consulting parents.

The party's new leader, Patrick Brown, notably did not broach the issue in his statement marking the first day of school.

He said last week he wants to "make sure parents have a say on how much and when."

Education Minister Liz Sandals urged parents who are opposed to the curriculum to first talk to teachers and principals because there is "a lot of misinformation" being circulated, but each school board does have a policy on withdrawing students from particular classes.

However, she said, the majority of the feedback she has received has been positive.

"I have never in my life been just stopped on the street by strangers so often [who] said, 'Thank you for doing this. Hang in there. We want this program."'

With files from The Canadian Press