Next Sunday marks the second anniversary of Argentina, with its strong historic cultural links with Catholicism, introducing laws to allow same-sex couples to get married.

It’s a mark of the success of this reform that 6,000 same-sex couples have tied the knot since then. In Buenos Aires, as in Madrid, Brussels, Reykjavik, Johannesburg, Ottawa, Lisbon, Amsterdam, Mexico City, Stockholm, Oslo and most recently Copenhagen, for those who believe in marriage, it has been strengthened as a social institution through greater equality.

It’s not often these days in the tough environment of Scottish politics that you get agreement between left and right, or between supporters of independence from or devolution within the United Kingdom. But it is testimony to the strength of the consensus brought together by the Equal Marriage campaign among our political parties and across wider society, that Scotland is likely to be the twelfth nation, and the first part of the United Kingdom, to legislate for same-sex marriage.

74 Members of the Scottish Parliament (MSPs) have declared their public support for equalising marriage laws, which provides a clear majority in the 129 member single-chamber legislature in Edinburgh. This political majority is strongly backed up by public opinion, including among rank and file members of the religious and faith community.

There will be full scrutiny of the Scottish Government’s draft Bill, including by parliamentary committees, which will allow expert evidence and the views of civic society, including those in the faith community, to be considered, prior to the Bill going before the full Parliament for debate. Changing the law in this way, as with every other social and economic issue, shows that representative democracy, while not perfect, works.

As a House of Lords Constitution Committee report in 2009 found, given our system of government, referendums are best restricted to intractable constitutional questions like a change in our relationship with the EU, the electoral system for Parliament, and reforming the second chamber. The end result of the political process is pretty clear – Scotland will make marriage, and civil partnerships, open to all couples who wish to make a public commitment of their love, whatever their sexuality.

That won’t be the end of the fight against inequality or homophobia in Scotland. Shelter’s figures tell a depressing story – 40% of all homeless young people are LGBT young people unable to live with their parents or other family members because of rejection.

All the more important then to resist plans to scrap housing benefit for under 25s. LGBT Youth Scotland found that 65% of young LGBT people in schools, rising to 70% in denominational or faith schools in Scotland, experience homophobic bullying that can emotionally scar for life.

One of the most moving cases I have dealt with as an MP involved a gay man who had just come out to his wife, children, and work colleagues, experienced hateful workplace discrimination causing him to leave his job, be awarded compensation by a tribunal for this, but failed to have the money paid to him, was then subjected to a violent homophobic assault in the street, and ended up penniless.

But equal marriage will mark the end of discrimination which has kept LGBT couples “separate but equal” in Scotland. It’s likely that Westminster will soon follow, when already 258 MPs like myself have publicly pledged to support equal marriage laws applying in the rest of Britain. For us, ending this discrimination is about basic human rights and our guiding principle of equality.

As Hillary Clinton told the UN last December on International Human Rights Day, as we are all born equal and free, we have rights, and governments are bound to protect them. I can think of no better rallying call than that which was the key message of the US Secretary of State’s landmark speech in Geneva – LGBT rights are human rights, and human rights are LGBT rights.

Willie Bain is the Labour MP for Glasgow North East and Shadow Scotland Minister.