Bear with me here. Here is a note from the MPAA.org site:
Alien vs. Predator
PG-13
Rated PG-13 for violence, language, horror
images, slime and gore.
Violence, horror images - PG13
Puppet Sex - X (toned down to an R)
Really people - have we not gone crazy enough? (FYI - Sneak preview on Saturday Night. B there or B sq.)