Does Mass Effect require an internet connection?

Does the PC version of Mass Effect require an internet connection to be played off line?

I don't have an internet connection at home... :-(
I had the game in my hands the other day, on the front cover it read: Requires internet connection.
My reasoning is the same... It's not a multiplayer game, why does it need i-net conexion? Does it use a STEAM like protexion system...???