Desperate Housewives producers have launched an investigation in an effort to find out how a sex scene from the upcoming season of the show were leaked onto Internet site YouTube.com. Executives insist the provocative scene, featuring MARCIA CROSS and Kyle MacLachlan, was not an official leak. It's the first time rough footage from an in-production TV series has appeared on the popular YouTube.com site. A spokesman for ABC, the network behind the show, tells industry trade paper Daily Variety, "We are looking into the unauthorised clips of Desperate Housewives on YouTube, and will be having them taken down."