http://themeparks.universalstudios.com/orlando/website/phi_guest_services.html
At Universal Studios®, children must be able to sit upright unassisted on all rides. Guests under 40" (1.02 meters) tall may not experience Back To The Future The Ride®. Guests must be at least 36" to ride Woody Woodpeckers Nuthouse Coaster® and 42" to ride Men In Black®: Alien Attack®.
Due to the nature of the attractions, expectant mothers are requested to avoid riding Back To the Future The Ride®, Earthquake® The Big One, Jaws® and use the stationary seating in Terminator 2:3-D Battle Across Time
At Universal's Islands of Adventure® children must be able to ride upright unassisted on all rides. Persons under 54" (1.37 meters) may not ride Dueling Dragons® or The Incredible Hulk-Coaster® , those under 52" (1.32 meters) may not ride Doctor Doom's Fearfall®, those under 42" (1.07 meters) may not ride Popeye and Bluto's Bilge-Rat Barges®, those under 44" (1.12 meters) may not ride Dudley Do-Right's Ripsaw Falls®, those under 42" (1.07 meters) may not ride Jurassic Park River Adventure® and those under 40" (1.02 meters) may not ride Amazing Adventures of Spider-Man®. Guests must be at least 36" to ride the Flying UnicornSM coaster. Pteranadon Flyers® is designed for children 36" to 56" tall. Adults over 56" must be accompanied by a child meeting this requirement. Due to the nature of the attractions, expectant mothers are requested to avoid riding The Incredible Hulk Coaster, Spider-Man, Doctor Doom's Fearfall, Dueling Dragons, Jurassic Park River Adventure, Dudley Do-Right's Ripsaw Falls, Cat In The Hat, Storm Force Accelatron®, Flying UnicornSM or Popeye and Bluto's Bilge-Rat Barges®. We have provided comfortable areas where you may wait for your party.