As Fr. Steve points out, the transgression of the man and the woman wasn't about gaining knowledge. The citation shows it was the tree of the knowledge of good and evil, not the tree of knowledge. (Apple Computer's logo and Isaac Assimov's misconception about knowledge and the pain of childbirth notwithstanding.) Humankind can't know the difference between good and evil without losing innocence (not ignorance) and choosing evil as an option. Likewise, their sin wasn't about sex but about wanting to be like gods (in control, no rulz!). Their embarrassment at being naked was because they suddenly noticed their bodies looked a lot more creaturely than godlike.

Like Texketz, I also don't see anything particularly ironic about clergy, etc. and clerk, etc. coming from the same roots. (The Scottish tartan for clergy comes from tartan for Clark (clerk), reflecting the reality that the clergy were often the only literate and the most educated members of their community. (Cf. "How the Irish Saved Civilization")