Under the Family Code, a child is considered legitimate if conceived or born during a valid marriage. A child is illegitimate if born to parents who are not married at the time of conception or birth, or if the marriage is later declared void (with some exceptions).

Children conceived through artificial insemination with the husband’s consent are considered legitimate. Children of voidable marriages that were later annulled may also be considered legitimate if conceived before the annulment.

Illegitimate children have the following rights under Philippine law:

Right to Support

Illegitimate children have the right to receive support from their parents. The support includes everything essential for sustenance, dwelling, clothing, medical attendance, education, and transportation.

Right to Inherit (Succession Rights)

Illegitimate children are compulsory heirs. Under Article 887 of the Civil Code, they are entitled to a portion of the parent’s estate. Their legitime (the reserved portion of the estate) is generally one-half of what a legitimate child would receive. For example, if a legitimate child is entitled to one-half of the estate, an illegitimate child is entitled to one-fourth.

Right to Bear the Father’s Surname

An illegitimate child may use the father’s surname if the father expressly recognizes the child through the proper legal process (RA 9255). The recognition may be made in the birth certificate, a notarized document, or a court order.

An illegitimate child’s rights depend on establishing paternity. This can be done through:

• Voluntary recognition — The father signs the birth certificate or executes a notarized acknowledgment.
• Compulsory recognition — If the father refuses to recognize the child, the mother or child may file a petition for recognition in court.
• DNA testing — Courts may order DNA testing to establish paternity in contested cases.