"I know who I pray to, and if other people want to pray to that chair over there, they're welcome to. It was my turn to do the invocation, and I did it the way I know how," Satterfield said.

But ACLU attorney Jennifer Rudinger fired back, threatening a lawsuit: "The law is pretty clear. The courts have ruled that it's legal to have an invocation at government functions, but it has to be non-sectarian."

His book, "The Future of Marriage," published last month by Encounter Books, explains why he doesn't believe same-sex marriage will serve that cause. But given the charged nature of the subject, his book may also set a record for optimism about the human capacity for rational discussion.

After examining the Mathematica study's methods, the Institute found several major errors that made the study non-representative of American sex education. First, says the more recent study, it took sample teens from "high-risk" sectors of the population, such as poor African or American single-parent households. During the study, young people received abstinence education in pre-adolescence, but then received no follow-up training during adolescence.

"As one who has been formed both through a deep Christian faith and as a scientist, I believe that science has revealed to us without equivocation that climate change and global warming are real and caused in significant part by human activities," said the Episcopal Church head.