The No Outsider project, established to teach tolerance of diverse groups, including those of different races, genders and sexual orientation, was suspended at Parkfield Community School “until a resolution has been reached”.
But now opposition to relationship lessons appears to be growing, with more protests planned across the country for later this week.
From September 2020, primary schools in England will be required to teach relationship lessons, including classes about friendship and families that will reflect that some children have same sex parents.
Parents will not have the right to withdraw pupils from those classes.
One father from Oldham told ITV News his children are too young to learn about same sex relationships and parents were angry as they felt their rights were being "breached".
Nasim Ashraf told ITV News: "We've had so many people protesting. And they're not all been Muslim, by the way.
"There are people from the Jewish community, people from the Christian community, atheists, agnostics, Hindus... they've all been saying exactly the same thing: 'our parental rights are being breached'."
There is concern that opposition to legitimate government policy is being hijacked by those with a religious, extremist agenda and the counter-extremism unit at the Department of Education is monitoring the protests.
Some headteachers are also concerned that the behaviour of a few parents is putting others under pressure.
Sarah Hewitt-Clarkson, headteacher at Anderton Park Primary School told ITV News some "really nasty tactics" had been used to coerce parents into adding their voice to the protests.
"Some parents have been harassed and intimated into signing letters they didn't want to sign," she said.
"Or if they don't take a leaflet they're being told horrific things, like you're 'rot in hell if you don't take this leaflet', 'you're not a proper Muslim'."