“Cecil Adams” is almost assuredly a pen name. Judging from what Cecil has written in his books, in his columns, and on this web site, he goes to great lengths to maintain his anonymity. However, in another thread someone claims to have seen him (or a picture of him), but I don’t think that’s possible.
I’m sure he’s at least 50 years old (he started his column in 1973, so if he graduated college at age 22 and started his column immediately thereafter, he’d be 48). He probably went to college in or around Chicago, possibly Northwestern, and probably majored in journalism. He probably lives in or around Chicago now, as he works for The Chicago Reader.
Well, from the hints he’s dropped in the column, I strongly suspect that he’s Catholic or ex-Catholic (some would argue that there’s no such thing as ex-Catholic, but that’s probably a topic for another thread). I’ll guess Irish-American, just 'cause I’d like to claim him as a compatriot…