I missed this programme but will listen now, via this clip. On Mark Thomas’s BBC Radio 4 Manifesto programme, audience member Laura proposed, to enthusiastic applause:

There should be a minimum age of consent before anyone joins a religion, because the vast majority of religions’ members were put through ceremonies by their parents when they were far too young to know what was going on. And while many of them renounce their faith when they are older, indoctrinating children allows religions to claim more members and more influence than is actually justified.

There’s a bit more about the idea here, in the Freethinker.