Every day at work as a doctor and at home as a parent, I am taught something all good footy coaches know: it’s what’s between your ears that matters most! There currently seems to be a lot of talk about what you need between your legs to be allowed to marry, when really we need to devote our attention to the brain.

The brain is the organ of greatest significance for human relationships and wellbeing. It’s the organ I’ve studied most in my training as an expert in the mental health of parenthood. And it’s the organ that will change at least slightly in each of us when we finally enshrine marriage equality as a society.

I am confident these brain changes will be positive for our children.

It’s about emotional safety, grounded in the best that brain science and clinical practice has taught me so far.

Emotional safety is the security of knowing your family – whoever is in it – will keep you physically safe, because your emotions tell you you are safe enough in that family. Life is so much less stressful that way, and people are much healthier in body and mind. I’ve trained as a psychiatrist, and that’s what my work is about.

I ask parents daily: can you think about what you and your child feel? Can you keep your child in mind? Can you ensure you act, both alone and in connection with other adults, to ensure your child feels safe and loved enough?

If so, your child will more likely feel respect for their humanity and their basic rights. They can be celebrated just for existing. They can be supported to learn from mistakes made amid the mess of daily human life. Crucially, they are not abused.

That is emotional safety.

At its core I think this marriage equality issue comes down to whose emotional safety matters more. Opponents of change seem to fear a breakdown in social fabric, and a loss of the emotional safety offered by tradition. Proponents of change fear ongoing loss of emotional safety steeped in millennia of persecution. Any resulting vitriol from either side speaks volumes about underlying fear – ad hominem attacks amid emotional danger.

For guidance amongst this complexity, I look to our babies.

I think of their emotional safety.

Our society is coming to accept the science of infant mental health: for us to survive and thrive we must put babies’ wellbeing first.

Ahead of everything else. All babies.

To put all babies born today first, and not some babies ahead of other babies, we simply have to grow as a society to welcome and respect diversity.

I don’t want to have to raise my children worrying about how the world will treat them if they are LGBTIQ. I want a world where it doesn’t matter whether my kids feel male or female or something else. Where it doesn’t matter if my kids like boys or girls or have moved past all that binary stuff and just want somebody who gets them.

The rest is noise. It’s noisy out there right now, but it will pass. My kids will be valued for who they are, and I’ll go to work with others striving to provide that for all our kids. Eventually the law will catch up. Childhood will be less stressful as a result, and our society healthier.

To finish, here are three predictions about the lasting effects of marriage equality, based on my observations as a father and a doctor with experience of hundreds of young families as well as my own.

1. Children who are born and grow up LGBTIQ will have less stressful lives from the outset.

Because they will grow up free of the looming deprivation of the right accorded their peers, to marry someone some day. Marriage equality helps recognise them as full humans, so all domains of life are likely to be less stressful for them.

2. Children born to LGBTIQ parents will have less stressful lives from the outset.

Because more people will have moved on from worrying about whether their parents’ relationship is unallowable or harmful. Fewer people will judge or mistreat them. Bullies take their cues from their seniors, and fear being left out. Once bullies see everyone else has moved on, they will have to tag along too.

3. All other children will be born into a more tolerant society, and have less stressful lives from the outset.

Because marriage equality leads the way towards treating all human difference with compassion and respect. So kids born with any kind of difference will receive more compassion and respect. The rest of our kids will grow from treating others with more compassion and respect. And all our kids will grow more securely, in less fear of the possibility that they could be different from others. We will all worry less about being different from others, and get on with life.

As always, I am grateful to the friends and colleagues who have helped me think and write about this.