Rodney Stark thinks we might be asking the wrong question.
All religious movements attract women more than men. It’s a subject I’ve tried to write on – we don’t really understand why it is that women are more apt to convert, although my student Alan Miller had a brilliant insight in saying, we should stop asking why women are more apt to be religious and ask why men are more apt to be irreligious. And he suggested that – why are men more apt to be criminal? That it’s kind of the same thing, it’s risk-taking, it’s short-sighted behaviour, and that men are more prone to it. It may even be biological for all we know, but it certainly is universal. Every religious movement I’ve ever seen any data on was disproportionately female, and that was certainly true of the early church. Not that they didn’t of course convert large numbers of men, because obviously they did. But, you know, to put it kind of frankly, Christianity was a good buy.