Because the issue at the heart of this debate is fundamental to who we are and what we believe. This is a debate about the principle of equality.

The aspiration and struggle for equality has been a constant in our history. Australia hasn’t always been an equal society, but ultimately we always move in the direction of greater equality. And we should not forget that it is a progression that is greater than any one vote.

This Bill is a step along the path of progress. That fact is demonstrated by what we have seen while this vote has been on the horizon.

Our numbers have grown, as the numbers of those who oppose marriage equality have got smaller. The momentum has been one way. Many of my colleagues who have previously opposed marriage equality, now support it.

I acknowledge them, and I thank them.

Because, like me, they know that the principle of equality is inherent in who we are. And it is central to the world we want for our children.

Because equality is more enduring than any single generation. It is a principle that will continue to inspire, and it is a fundamental right.

If you look at the span of history, of social change, the calls for equality have been persistent and they have been successful.

We have seen changes to ensure individuals are not discriminated against because of their gender, their race, or their religion. Reforms that see all Australians treated equally in the community and in their workplaces. The quintessential Australian idea of a ‘fair go for all’.

Much has been said in this debate about relationships, about families, about parenting, and about the so-called ‘threats’ to the nature of Australian society.

But let’s be clear about what we are debating here.

We are being asked to consider whether the state, through law, should continue to discriminate against some Australians solely on the basis of their sexuality.

We are being asked to consider whether in today’s Australia, we should continue to ban two consenting adults from marrying because – and only because – they are of the same sex.

If you subscribe to the principle of equality – as I’m sure most in this chamber would – then substitute ‘same sex’ for ‘race’ in this debate and see if it changes your view.

Just imagine if we told Australians today they could not get married because the person they love is of a different colour skin.

Imagine if we told Australians today they couldn’t get married because the person they love is of a different religion.

Such notions are rightly seen as anachronistic. And in 2012, it is truly sad that some still feel the need to constrain the freedom of others to make a commitment to the person they love through marriage.

I do believe marriage is unique. I believe that marriage is special, and that it is a bedrock institution of society. I believe that marriage should be valued.

But marriage does not need to be ‘walled off’ from some Australians in order to preserve its worth.

The heart of marriage is the love of and commitment to another. This promise, the vow of marriage, does not discriminate – and nor should our laws.

But the Marriage Act, as it is currently worded, is discriminatory. It involves different treatment and lesser rights to certain individuals on the basis of their sexuality.

The discrimination could not be more real.

There are many arguments that have been put in this place, and in the debate more broadly, by those seeking to continue marriage inequality.

People have argued that same sex marriage would undermine the institution of marriage; that marriage as a concept is immutable and therefore unable to accommodate gay and lesbian Australians.

And then there is perhaps the most hurtful of arguments – the view that marriage is an institution of procreation and therefore same sex couples are not welcome

I believe it is worth discussing these arguments each in turn because when held up to scrutiny, they are clearly without foundation.

As I have said, some have tried to claim that allowing same sex couples to marry will somehow destabilise the very foundation of marriage. That it will undermine what marriage is.

But this is not a zero sum game.

My getting married does not preclude a heterosexual couple from getting married.

Indeed, the argument that allowing me to marry the person I love will somehow make their love less says more about their relationship than mine.

So I say to those who oppose this Bill: You do not need to legitimise your relationship by undermining mine.

You do not need to tell me and the thousands of other same sex couples that our relationships are less worthy, less valid, less important.

We know the worth of our relationships. And we will not allow them to be diminished in this debate. And we do not accept them being diminished by this law.

As I said, I agree that marriage is both unique and important. Same sex couples believe marriage is an important institution. And that’s why we want the choice to enter it.

….

Some also argue that marriage is about children, and that same sex couples can’t, or shouldn’t, have children.

This is an argument that brings with it a fair amount of logical confusion.

To suggest that you can or should only have children if you are married is inconsistent with reality of today’s Australia.

To suggest that marriage should be defined only by reference to children would mean marriages in which someone is infertile would not be allowed.

Marriages where the couple did not want to have a family wouldn’t be allowed.

Marriages where the couple were too old to have children wouldn’t be allowed.

Clearly this is not the case.

But underlying this position – and perhaps the most hurtful argument of all – is the view that some Australians aren’t worthy of being parents simply because of their personal attributes.

That is, because of our sexuality, our worth as a mother or father is lessened.

Well, the fact is, same sex couples already have children. And denying marriage equality will not change this.

Bringing an argument about the worth of our families, about the value of our parenting in to this debate is nothing more than dishonest and objectionable.

The quality of parenting, whether by a straight person or a gay person, will never be determined by a political argument.

A parent’s love for their child, straight or gay, is seen in the days and nights and years of love and nurture and hope and so much more.

…

The arguments of those that oppose this Bill do not stack up.

Gay and lesbian Australians are no different to all other Australians.

We come from all walks of Australian life, from all regions, all income brackets. We are your daughters and your sons, your brothers and your sisters, your mums and your dads, your co-workers and your friends. And we have the same aspirations, the same ambitions, the same hopes.

We are not so different. And it is time to recognise this.

…

Those who oppose this Bill speak to the past. I and my colleagues are talking to a better future.

Because whatever happens in the Parliament this week, our relationships are not inferior, our relationships are not less equal, and our love is no less real.

We will get there. Perhaps not in this Parliament, but one day. One day, we will be recognised as equal.

For us, this is the most personal of debates. It is about the people we love most in the world – the people who give meaning and hope to our lives. It is about our families.

And, ultimately, it is not only about what we want for ourselves, it is about what we want for our children.

We all hope for our children an easier path; that the challenges life presents will be surmountable.

I do not regret that our daughter has Sophie and I as her parents.

I do regret that she lives in a world where some will tell her that her family is not normal.

I regret that even in this chamber, elected representatives denigrate the worth of her family.

These are not challenges she deserves. None of our children deserves such challenges.

So I will not rest in the face of such prejudice.

I want for her, for all of us, an Australia which is inclusive and respectful.

And this is why this campaign will not end here.

Because we who argue for equality are not only standing for principle, we are also standing for the people we love. And there is nothing more powerful than this.

So, I say to those opposing this Bill: You have nothing to fear from equality.

Let us judge relationships by the markers which matter: love, respect, commitment.

Let our laws reflect these most cherished values. And give voice to the equality that is due.

This is an edited version of the speech Senator Penny Wong delivered yesterday as the Marriage Amendment Bill was voted down by the Senate. The full version of the speech can be found on Senator Wong's website (some paragraphs have been removed for length. No wording has been altered).