Wright's conversion story (warning, have barf bag ready before reading, it's pretty bad even by SN standards) went up on SN in the relatively early days. One of Wright's claims in it is that as an atheist he had argued himself, by means of nothing but ‘pure’ ‘rational’ philosophy into positions otherwise held by Christians; his conversion story doesn't go into details about what those were, but from his other writings it seems clear that sexual matters were at least a significant part of this.
So I was interested (and amused) to see that Ozy Frantz has done a long takedown:
John C Wright is an absolutely delightful person whose blog posts have given me endless hours of enjoyment and who has recommended many excellent short stories (admittedly, by talking about how they are the Morlockian death of science fiction, but a good recommender is a good recommender, even if it’s wired backwards). I have recently discovered an old blog post of his which purported to lay out natural and worldly reasons why a rational atheist should follow Christian sexual morality. As an atheist libertine, I find this a tremendously interesting proposal and wish to argue with it.