Jon Rauch (who, among other things, is IGF's co-managing editor), dissects Stanley Kurtz's misuse of data to claim that same-sex marriage undermined traditional marriages in the Netherlands, leading to an increase in out-of-wedlock births. It gets technical, but you can read Jon's analysis first here, then a follow-up here, and a final retort here.
But the rank distortion on Kurtz's part really isn't surprising.
As one of the comments to Jon's posting puts it, "The arguments
against same-sex couples marrying legally are not based on reason
or on data. When you have faith, anything will do to feed
it."