Nor can old couples or infertile couples, and nobody is questioning their right to marry.
"You can't just change the rules associated with a traditional institution."
In fact change happens constantly as societies evolve, moods shift and opinions develop. Institutions, governments, rules and laws all must respond to reflect contemporary attitudes and outlooks. Some people call it progress.
"The introduction of same-sex marriage will negatively impact my marriage."
Sorry to hear you're having marriage difficulties. The relationship must be in a rocky state if some random law change will harm it. Have you considered counseling?
"It's a slippery slope. If same-sex marriage is allowed what might it lead to?"
William Dameron wrote in the Huffington Post: "I do have my own hopes for what marriage equality will lead to ...: greater acceptance of LGBT people and their families, better mental health of LGBT citizens, less bullying of LGBT teens, lower teen suicide rates ... and local economies experiencing a boost due to LGBT weddings. If any of these things lie at the bottom of that slope, then let it slide."
"Marriage is a sacred institution that shouldn't be tinkered with."
Tell that to the 17,102 people who were involved in the 8551 divorces recorded in New Zealand in 2011 alone.
"They should be happy enough with a civil union."
Following that logic those of us in opposite-sex marriages should have been satisfied with a civil union yet something drove us to choose marriage. Not allowing all citizens to express their relationship in the same way is discriminatory.
"It will erode respect for marriage."
If anything is likely to erode respect for marriage it would be jealously guarding it on flimsy pretexts and preventing certain groups from participating in it.
"Marriage is supposed to be between a man and a woman."
That is patently unfair. People in same-sex relationships should have the opportunity to be just as miserable as the rest of us.
"They're just trying to steal another word. And, by the way, they've already stolen 'gay'."
No one owns words and therefore they cannot be stolen. People just use words, and words evolve organically over time and through common usage.
"Next thing you know there'll be marriage for dogs."
Please keep up. It's happened already. See Modern Dog magazine for a report on loved-up pooches taking their "bow vows".
"The sky will fall in."
The sky didn't fall in when marriage equality was achieved in Argentina, Belgium, Canada, Denmark, Iceland, the Netherlands, Norway, Portugal, Spain, South Africa and Sweden so we'll probably be safe, too.
Debate on this article is now closed.