This site contains the account - from the back of Lawrence Kelemen's Permission to Receive - of Rabbi Kelemen's correspondence with the Roman Catholic Church about several apparent inconsistencies within the New Testament. The Church referred Rabbi Kelemen to two books by Dr. Raymond E. Brown, both bearing the Vatican's stamp of approval. The site quotes a few different ideas from Dr. Brown's books, including the assumption that Jesus' birth was not virginal (contrary to popular Christian belief). Dr. Brown cautions, however, that "we should not underestimate the adverse pedagogical impact on the understanding of divine sonship if the virginal conception is denied." And the site reports that
"Brown also considers the possibility that Christianity's founders intended to create the impression that an actual virginal conception took place. Early Christians needed just such a myth, Brown notes, since Mary was widely known to have delivered Jesus too early: 'Unfortunately, the historical alternative to the virginal conception has not been a conception in wedlock; it has been illegitimacy.' Brown writes that:
"Some sophisticated Christians could live with the alternative of illegitimacy; they would see this as the ultimate stage in Jesus' emptying himself and taking on the form of a servant, and would insist, quite rightly, that an irregular begetting involves no sin by Jesus himself. But illegitimacy would destroy the images of sanctity and purity with which Matthew and Luke surround Jesus' origins and would negate the theology that Jesus came from the pious Anawim of Israel. For many less sophisticated believers, illegitimacy would be an offense that would challenge the plausibility of the Christian mystery." [emphasis added]
I quote this because of recent events in orthodox Jewish circles. The devoutly Catholic sentiments of Dr. Brown - his fears of the consequences of revealing the unromanticised facts about Christian doctrine to the public - make me think of the banning of Rabbi Nosson Slifkin's books (and of Rabbi Nathan Kamenetsky's The Making of a Godol), which it seems likely was for almost exactly the same reasons.