As I mentioned the other day, I finally pushed myself through the book. It's hard for me to see how anyone is threatened by it. It's nothing more than a fairly linear (and tedious) detective story that happens to be set within a fabricated set of mysteries surrounding the history of Christianity. It's a simple book; the kind of thing people read at the beach. As A. O. Scott said, it would probably take longer to see the movie than read the book.
Nevertheless, it seems to be fashionable to say something about it, so here goes:
1. To say that the "sacred feminine" is a hushed secret within Christianity is not quite accurate. For one thing, it's no secret. The Da Vinci Code acts at one point like the allegorical interpretation of Church architecture as feminine anatomy is some kind of secret. Mystical writers have long seen Church buildings as the womb of Mary, out of which we believers emerge as the newly born Body of Christ. Even someone as strict as St. Francis called Mary the virgo ecclesia facta, or "virgin made church."
Furthermore, the suppression of the feminine face of God is hardly the fault of Christianity. Historians of theism tend to see this suppression as occurring around the time of the first agricultural revolution, when people first settled down and came into more control of animal and plant fertility. Holding onto land became more important than the fickle fertility cycles of nature, and thus feminine fertility gods gave way to masculine war gods. All this is, of course, long before Christianity. Diarmuid O'Murchu has written about this, though I forget in which book.
2. The portrayal of Opus Dei has been annoying for them and a joy for their detractors. But the main Opus Dei character in the Da Vinci Code is described as a monk, and there is no such category of membership in Opus Dei. On the other hand, wild rumors and accusations are part of the price an organization has to pay for being so secretive.
3. The Da Vinci Code suggests that Jesus of Nazareth was married to Mary of Magdala, that they had children, and their descendants came to be the Merovingian dynasty in what became modern France. First of all, there is no way of knowing any of this. Historically speaking, both characters are hard to pin down biographically. Even if it is true, that their descendants became the kings of France seems far fetched. It's the same kind of creative salvation history that likes to variously identify the ten lost tribes of Israel with the British, the Jamaicans or the Native Americans.
Even more, to allege that Jesus was married and had children does not interfere with any dogmatic Christological claim as far as I can see. The only thing such a claim does is dismiss the imitatio Christi strand of the Christian celibacy tradition. But that's only one aspect of the tradition on celibacy.
4. It's hard to see how the Da Vinci Code didn't make a good movie. The book reads like a movie, constantly cutting between one scene and another. Maybe the casting was all wrong. Tom Hanks doesn't seem geeky enough to be Robert Langdon. Paul Bettany doesn't seem tough enough to be Silas. Ian McKellan is too stately to play the short, fat, half-crippled Leigh Teabing. On the other hand, Audrey Tautou is just as I imagined Sophie.