Copied from Department of State website:
The Government of Puerto Rico recently passed a law invalidating all Puerto Rican birth certificates issued prior to July 1, 2010, and replacing them with enhanced security birth certificates with features to combat passport fraud and identity theft.
Beginning October 30, 2010, the Department of State will no longer accept Puerto Rican birth certificates issued prior to July 1, 2010 as primary proof of U.S. citizenship for a U.S. passport book or passport card. Only Puerto Rican birth certificates issued on or after July 1, 2010 will be accepted as primary evidence of U.S. citizenship. The requirement does not affect Puerto Ricans who already hold a valid U.S. passport.
For more information on the Department‘s policy for accepting Puerto Rican birth certificates, visit travel.state.gov/puertorico.
For more information on the Puerto Rican law, and instructions on how to order a new Puerto Rican birth certificate, visit www.prfaa.com/birthcertificates (English) or www.prfaa.com/certificadosdenacimiento/ (Spanish)