The latest offensive and ill-informed stream of bile from George Christensen and Cory Bernadi is a powerful reminder of the harm words can do.

Some might prefer to ignore their statements, or dismiss them as deliberately provocative, but these are elected members of the government of Australia, choosing to use their position in parliament to pursue a prejudicial vendetta against the Safe Schools program.

Safe Schools has been labelled a lot of things: Marxism, cultural relativism, “grooming” and part of something called the “rainbow ideology”.

But Safe Schools is not about imposing an ideology, or an “ism”. It’s about teaching our kids to treat everyone equally, to understand rather than judge. It is an important program, designed to prevent the bullying and intimidation of children who are struggling with questions of identity and sexuality.

Safe Schools lets young people who identify as gay know that they have every right to be accepted and respected for who they are. We should never underestimate how important this message is – or the consequences of trying to shout it down.

Anyone who’s been a teenager, or raised one, knows growing up is hard. Kids can be cruel to their peers, and many young people go through tough times and experience low moments.

But a young Australian who identifies as gay is six times more likely to consider taking their own life, compared to their sibling, classmate or teammate. Two out of five young Australians who are gay have thought about self-harm or suicide.

For kids in the regions and the bush, physical remoteness can add to a sense of isolation.

Both casual, unthinking discrimination and deliberate, malicious homophobia erode self-confidence and undermine mental health. Both are far too common, not just in our schoolyards or online but in sporting clubs, in the outer and even in our national parliament.

If one government program, designed to teach respect and inclusion, is capable of provoking the sort of unhinged and unfounded abuse we saw from an angry few last week, I shudder to think what kind of animosity Malcolm Turnbull’s plebiscite on marriage equality will stir up.

There’s no doubt in my mind Turnbull’s plan for a $160m taxpayer-funded opinion poll is a waste of money. But the real cost could be much higher, if harder to measure.

How do we quantify the damage done to a young person’s sense of self, if they are subjected to taxpayer-funded advertising arguing that they are a second-class citizen?

How can we guess the effect on children of seeing Australian-government sponsored advertisements claiming their parents are not fit to marry?

How do we measure the harm inflicted by a long and poisonous debate, where all the offensive prejudice of the past week will be amplified and magnified?

It is hard to know the toll this will take on the psyches and self-confidence of so many – but it is easy for our parliament to do something about it. As elected representatives, we have a responsibility. Not just to be mindful of our words but to do the right thing with our actions.

This is why our parliament should have a free vote on marriage equality, now. The legislation is already in the chamber and I believe the numbers are there to pass it. This week, my shadow parliamentary secretary, Terri Butler, will be re-introducing her bill for marriage equality into the parliament.

But if Malcolm Turnbull wants to introduce his own bill, I would be happy to second it.

Imagine if at Mardi Gras next Saturday, instead of dreading a drawn-out and divisive plebiscite, Australians were celebrating marriage equality at last.

Imagine if by the start of term two, Safe Schools was recognised and secure.

This is far from impossible. If Malcolm Turnbull is prepared to show a bit of leadership and a bit of courage, it can be done quickly and easily.

Let’s make marriage equality a reality. It’s time.

This opinion piece was first published in The Guardian on Monday, 29 February 2016