There was a very interesting article in pinknews: http://www.pinknews.co.uk/2011/09/28/scottish-faith-groups-call-for-gay-marriage/
In one of the comments an essential critical opinion was written about the official catholic point of view:
The catholic leader says this is a “grotesque subversion of a universally accepted human right”. To say to a fellow human being `You must spend your entire life alone – without love, affection and intimacy with another human being’ – which is the catholic church’s message to gay people – THAT is a “grotesque subversion of a universally accepted human right”. (Peter)