Otherwise, the most intriguing aspect of this calculated mix of raunch and adorability lies in the rivalry between Kutcher and his dad (Kevin Kline), surely some kind of submerged metaphor about Ivan Reitman crossing into his son Jason�s slick Up in the Air turf.
Mr. Reitman is not his son Jason (“Up in the Air,” “Juno”).
Reitman, a veteran of hit comedies (and father of Jason, who directed Up in the Air), knows how to pace and edit around jokes for maximum comic effect, and the script is unusually sharp for the rom-com genre, stuffed with memorable lines and situations — most of them gleefully R-rated — that give the actors something to do other than riff and flail around in cute fashion.
Do not confuse him with Jason Reitman, who made the refreshing Up in the Air.
Right now, “No Strings Attached” director Ivan Reitman (“Ghostbusters”) probably hopes to emulate his son Jason’s recent success (“Juno,” “Up in the Air”), and Oscar favorite Portman (“Black Swan”) hopes not to damage her rising star with a stinker.