To cure the ills of single-parenthood, benefit-dependency and the like, he proposes a tougher welfare regime (though not all that different from the government's), tangible if unspecified support for marriage through the tax system and more job flexibility for parents.

ECONOMIST: David Cameron

"As the demand for same-sex marriage is uncertain, and because these economic benefits are not guaranteed to be additional (for example, the spending on a civil partnership or marriage ceremony may not be additional if the couple and guests cut back on spending in other areas), we use zero benefit as our best estimate, " it explains.

BBC: Gay marriage: Eight things for better, for worse

If this seems outrageous to you, keep in mind that President Barack Obama did not come out for same-sex marriage until the final months of his first term.

CNN: Media walk tricky line on same-sex marriage