I direct your attention here.
The Pope addressed a crowd of 180 religious diplomats from around world, that:
"This is not a simple social convention, but rather the fundamental cell of every society. Consequently, policies which undermine the family threaten human dignity and the future of humanity itself," he said.
Emphasis mine. My extremely well thought out and comprehensive rebuttal below the fold.
I lied, my rebuttal is neither well thought out nor comprehensive. Just two thoughts.
Human Deaths Directly Caused by Gay Marriage: 0
Human Deaths Directly Caused in God's Name or by Religious Zealots: 1,000,000,000+
Where's the greater threat from, then?