Philippine Constitution: Article IV
January 1, 2009
Section 1. The following are citizens of the Philippines :
(1) Those who are citizens of the Philippines at the time of the adoption of this Constitution;
(2) Those whose fathers or mothers are citizens of the Philippines ;
(3) Those born before January 17, 1973, of Filipino mothers, who elect Philippine citizenship upon reaching the age of majority; and
(4) Those who are naturalized in accordance with law.
Section 2. Natural-born citizens are those who are citizens of the Philippines from birth without having to perform any act to acquire or perfect their Philippine citizenship. Those who elect Philippine citizenship in accordance with paragraph (3), Section 1 hereof shall be deemed natural-born citizens.
Section 3. Philippine citizenship may be lost or reacquired in the manner provided by law.
Section 4. Citizens of the Philippines who marry aliens shall retain their citizenship, unless by their act or omission they are deemed, under the law, to have renounced it.
Section 5. Dual allegiance of citizens is inimical to the national interest and shall be dealt with by law.