If you care for your teen well, it will have an influence on the kind of adult it evolves into.
By "care well" I mean keep it's happy and hungry hearts full, get training points when it beeps for attention and play games with it at least a couple of times each day.
Why not visit Rivenn's site (he's a TamaTalk member) - it's called Tamadex - and has a V2 growth chart (still under construction) and a list / pictures of all the V2 characters (and what each one can evolve into):