PARENTS are furious over anti-gay marriage literature being pushed onto their children on behalf of the Catholic Church.

An 18-page document called Don’t Mess With Marriage, detailing the church’s stance on the same-sex marriage debate, has been distributed to Catholic schools Australia-wide and has been slammed by parents as “propaganda”.

The “pastoral letter” published by the Australian Catholic Bishops Conference refers to same-sex marriage as a “serious injustice”.

Addressing issues of discrimination, the importance the traditional family structure, and the consequences of redefining marriage, the document rejects the notion that reserving marriage for heterosexual couples is discrimination.

The letter argues it is “gravely unjust” to “legitimise the false assertion that there is nothing distinctive about a man and a woman”.

It also argues that destabilising marriage “at a time when it is already under considerable pressure” and changing “the basis upon which all existing married couples got married” are injustices.

Canberra mum Tanya Howell was “furious” to discover the letter had been handed out at her daughter’s school.

“I didn’t actually know what to say because I’m just shocked that in this day and age, knowing that they have children in that school who are gay people, that this sort of discrimination would be promoted,” she told news.com.au.

Ms Howell’s daughter, year 12 student Maddison Fisher, was handed the booklet during a school assembly at Merici College in Canberra Thursday morning.

“I’m just furious. I am disgusted with what they have done,” she said.

“This society is trying to eliminate discrimination and to be honest that’s what the church is continuing to encourage — discrimination. If it’s Catholic teachings and what’s in the Bible that the school is meant to be complying with, it’s contradictory.”

Ms Howell was notified about the notebook when Maddison’s brother Jay posted a Snapchat of the booklet that Maddison had sent on Facebook.

The 22-year-old gay man said he was “very unimpressed” with the message.

“I understand the religious values at the college she is educated in, although I feel this type of campaign is more malicious rather than educational,” he wrote.

Maddison told news.com.au most students were confused when the pamphlets were distributed and thought it was “a bit inappropriate”.

“My first thought was that due to same-sex marriage being such an issue at the moment that obviously the church must be getting desperate if they’re reaching out to children,” she said.

Maddison said she was particularly shocked by the call to action at the end of the 18-page document: “We particularly urge you to make your views known to your parliamentary representatives.”

The instruction follows pages of arguments against allowing same-sex marriage, including 15-point list of real life recent examples of the consequences of gay marriage.

The letter does acknowledge people with same-sex attraction must not be discriminated against, and that “they need love and support like anyone else”.

“But pretending that their relationships are ‘marriages’ is not fair or just to them,” it says.

“As Christians we must be willing to present that truth about marriage, family and sexuality and to do so charitably and lovingly.”

Australian Marriage Equality national director Rodney Croome said Catholic bishops seemed to be completely unaware of the damage their attitudes could have on young people in their schools.

“I’m talking about young same-sex attracted people, for whom life is already hard enough, and also the children of same-sex couples,” he told news.com.au.

“But given this material has already gone out it’s only fair marriage equality advocates are invited in to Catholic schools to give their side of the issue. After all, education is about hearing and understanding both sides of an argument, not just being fed one line.”

A spokeswoman for the Australian Catholic Bishops Conference told news.com.au the letter was drafted by the Australian Catholic Bishops’ Commission for Family, Youth and Life and was created as a “guidance document” for “all Australians”.

The letter was sent to each bishop in Australia and it was at their discretion as to how the letter was distributed, the spokeswoman said.

Canberra Archbishop Christopher Prowse said the booklet had been distributed across 56 Catholic schools in his archdiocese earlier this week.

“We’re hoping it will be distributed to all our Catholic institutions, our communities, and our parishes,” he told the ABC.

Ms Howell has written to Merici College to complain. The school’s principal was unavailable for comment when contacted by news.com.au.

What do you think? Tell us your thoughts in the comments below or continue the conversation on Twitter @newscomauHQ