Say It Isn't So (2001)
Overview : Boy meets girl; boy falls in love (and had wild, non-stop sex) with girl; boy loses girl... when they discover they are brother and sister! But when he learns that he's the victim of the ultimate case of mistaken identity, the lovesick young man -- whom everyone still thinks is after some taboo thrills -- must race across the country to stop her from marrying another man.
Release Date : March 10, 2001
Runtime : 95m
Companies : Say It Isn't So Productions, Conundrum Entertainment, 20th Century Fox
Countries : United States of America
Keywords : mistaken identity, crude humor, taboo, cross country, lovesick