Ontario Premier Kathleen Wynne is firing back at Progressive Conservative Leader Patrick Brown, who has promised to spike the Liberals' sex-ed curriculum if his party forms the next government.

In a letter distributed earlier week, with days to go before a byelection in the riding of Scarborough-Rouge River, Brown wrote that "a PC government would scrap the controversial changes to sex-ed introduced by Premier [Kathleen] Wynne and develop a new curriculum after thoughtful and full consultation with parents."

Speaking to CBC News from the riding Saturday, Wynne says scrapping the curriculum, which was updated last year, "would put kids at risk."

"It's been consulted on with parents, with educators, with social workers, police, health care workers — it's a very important development. To scrap it ... would be very, very dangerous."

Progressive Conservative leader Patrick Brown (left) campaigning with Scarborough-Rouge River candidate Raymond Cho (centre), a few days before the byelection in that riding. (CBC)

The curriculum was updated last year, for the first time since 1998, to include same-sex relationships, the dangers of online bullying and sexting. Its introduction was divisive, sparking protests and motivating some parents to withdraw their children from school. One Toronto elementary school revised its curriculum this spring in a bid to keep kids in classes.

'He was just learning body parts'

Residents of Scarborough-Rouge River are split on the new curriculum. It also isn't clear how many of them will base their vote on the issue.

Of the parents CBC News spoke with on Saturday, some expressed concern about schools encroaching on material best taught by parents, while others described this week's letter as a political ploy.

Flora Vaz's children are registered in the Toronto Catholic District School Board. She says she was "shocked" when the revised sex-ed curriculum was introduced.

"I think it violates the sanctity of sex in a marriage ... There's something that should be there, a mystery. To start now, when they're so young, children might want to experiment — that's the fear."

Flora Vaz was 'shocked' at the new curriculum and thinks sex ed should be taught by parents or when children are older. (CBC)

Vaz wouldn't say whether she's voting for the Progressive Conservatives specifically, but did say she'd only vote for candidates who promise to scrap the revised syllabus.

It's far from a universal sentiment.

Bill Mboutsiadis is a father of two and although he doesn't live in Scarborough-Rouge River, his mother does. His son, John, just finished Grade 1 and learned some of the new curriculum last year.

"He was just learning body parts, which is fine. Instead of using strange pseudo-names they used proper biological names."

Mboutsiadis says he's strongly in favour of keeping the curriculum and is encouraging his mother to vote accordingly. "It's about time we changed it ... it's all evidence-based."

Byelection on Thursday

Mboutsiadis says he is also frustrated at the focus on sex-ed rather than issues like infrastructure and school repairs, describing it as an election tactic.

"It's just games ... Fix the roof; fix the boiler."

Bill Mboutsiadis is a father of two boys; he's a proponent of the sex-ed curriculum and thinks the biggest issue schools face are infrastructure problems like leaking roofs. (CBC)

There is also some confusion about exactly what Brown is proposing.

Despite promising to scrap the curriculum in the letter that went out a few days ago, on Saturday he told CBC News that it was "a form letter that was used in a byelection. What I'm committed to doing is making sure that in the next curriculum, that we would engage parents and that parents would be given a voice."

On Saturday, a Liberal spokesperson said the PC leader is flip-flopping, a charge Brown denies.

Voters in Scarborough-Rouge River go to the polls on Thursday.