Patrick Geary--the author of Women at the Beginning--is one of the pre-eminent historians of the medieval period, but it is difficult to know how seriously, if at all, he takes the historical claims of the Christian religion. There isn't any empirical evidence, after all, to support the boldest of the claims. So perhaps it should come as no surprise to find the Virgin Mary being mentioned alongside the Amazons as an example of a woman in an origin myth. In the introduction to the book he cites no Scriptural texts, only Gnostic ones, so it seems he takes the "Mary Story" as just one more example of a trope from antiquity. His project is at least partly sociological:
The men who wrote about these women often held ambivalent attitudes toward them, attitudes that are evident in the contradictory images produced and reproduced across the centuries. As the French historian Jean-Claude Schmitt has written concerning the powerful but ambivalent images of Eve and Pandora, when studying these accounts the historian must understand the different meanings that they held for the societies that produced them, taking into account in particular the variants chosen or invented in the course of their reception. The representations of women in stories of beginnings, as Amazons or saints, monsters or troublemakers, are too complex to categorize. They remain problematic and contradictory figures. And yet they continue to fascinate, to tempt us to consider them, to ask what the place of women at the beginning tells us about women, about beginnings, and about the present and future.All of this is perfectly consistent with seeing Mary as a historical figure, of course, or even with seeing all of Christianity as historically true. It's just that it's also consistent with regarding the whole religion as a myth, and it's difficult to know which way the author himself would go on that one.
Does it matter? Can one benefit from reading a book written by a non-believer if that book is logically consistent with a book written on the same topic by a believer? Certainly. Is it somehow dangerous to read that kind of book? That might depend, I suppose, on whether one thinks that there is a real danger of someone coming to disbelieve the truths of Christianity on the basis of the reading of the book, and precisely what that danger is believed to be. When someone reads a book, I suppose it might be possible for their minds to be completely turned around by the text in some powerful case of negative metanoia, but I suspect that it is much more probably that a single book can serve only to tip in one direction an already tottering scale. It seems silly to lay full blame for the result on one book alone. But if the scale gets tipped, need we really fear that the person riding in the scale is lost forever?
Generally speaking, when someone has been duped by a con artist, we don't hold the victim guilty of any wrongdoing. Generally speaking, we would say that the con artist has done the morally blameworthy thing, and the victim should be receiving pity, not punishment. In the case of religious belief, however, it may not be so simple. What you believe, apparently, can make a real difference to the relationship that exists between you and God. But possibly God is not so literal minded that he won't make any allowances at all for the fact that simple people often get defrauded. If the Church can abandon all of Saint Thomas Aquinas' hard work on the nature of limbo on the grounds that God may possibly want to save even those who have not been baptized, then perhaps we are permitted to believe that someone who has been tricked into not believing what he ought to believe may yet be forgiven for having been too trusting of the wrong sorts of sources.
We are judged, I take it, by what we make of the real Gospel, not by what we do with the false gospels that are constantly coming our way. We are cautioned to watch out for the false prophets and the teachers of untruths, to be sure, but the overall message appears to be that only by rejecting the true Gospel can you reject God himself, and you cannot be held guilty of rejecting the true Gospel if the true Gospel was never preached to you. Ought implies can, and if you cannot understand the difference between the true Gospel and the false Gospels, then your moral burden is arguable lessened. God does not try us beyond what we are able to bear.