Indeed the Catholic Church will need to change it's archaic views if it wants to remain relevant in today's world.
That church learnt, to it's great dismay, what happens if they upset even a staunch Catholic nation like Ireland.

On finding out the truth about paedophile priests and fornicating clergy having their own illegitimate children, yet stealing babies off unmarried mothers, and forcing death on young pregnant women rather than allowing abortion, the Irish nation voted in gay marriage.

LEGO "Look Peter, most people in the western world are tolerant of homosexuals. Tolerance does not equate to approval. We will not accept that homosexual unions are "marriage". And the more you try to push it, the more that normal people become less tolerant of homosexuals."

I assume you think you are 'normal' because you were born heterosexual then LEGO?
Who says so? What is normal for you may well be abnormal to others.

"And every non human rights argument that you could advocate could equally apply to incestuous couples."
No, not true. No human rights organization would ever advocate equal rights for incestuous couples, given that their union would very likely cause genetic disorders in any children they may produce, hence why the practice is illegal.

Suse,

The illegality of incestuous unions is ridiculous, if two people love each other.......

Is Mise, I wasn't talking about love any where on my post, so what is your point?
Allowing the legalization of gay marriage will never bring on the same for incestuous couples, for the reasons I already gave.
Love has nothing to do with it.

Suse,

What about father son relationships?
Grandfather and grandson?
Male first cousins?
Female first cousins?
Etc.
Uncles and nephews, aunts and nieces, mothers and daughters, grannies and granddaughters?

A relationship doesn't have to be heterosexual to be incestuous.

As I said, if two people love each other; or don't you believe that homosexual and lesbian unions are alright?

Lol Is Mise, you are really clutching at straws now!
Lucky you don't live in Ireland...

Clutching at straws?

You're the one who said incestuous relationships were wrong because of the chance of children of such relationships and I gave you a pile of incestuous relationships to which your criteria do not apply.
What's your answer?

Then there are heterosexual people who are past childbearing age, why should they not be able to have an incestuous relationship if they so desire?

What is the harm?

Why are you against such people finding happiness?