Certain marriages are void from the very beginning because of the relationship between the parties, regardless of consent or good faith. Incestuous marriages are void: these include marriages between ascendants and descendants of any degree (such as parent and child, grandparent and grandchild) and between brothers and sisters, whether of the full or half blood. Separately, marriages void by reason of public policy include those between collateral relatives up to the fourth civil degree (such as first cousins), between step-parents and step-children, between a parent-in-law and child-in-law, between an adopter and the adopted (and certain adoption-related relationships), and between parties where one killed the other's spouse to marry them. These marriages are void whether or not the parties knew of the impediment.
Some marriages can never be valid — not because of a defect in the ceremony, but because of who the parties are to each other. These are incestuous marriages and marriages void by public policy.
Void From the Start
Unlike voidable marriages (which are valid until annulled), these marriages are void ab initio — void from the beginning. No amount of consent, good faith, or later ratification can validate them. Anyone with an interest can generally have them declared void.
Incestuous Marriages
Marriages that are incestuous and void include those between:
- Ascendants and descendants of any degree — e.g., parent and child, grandparent and grandchild; and
- Brothers and sisters, whether of the full or half blood.
These are prohibited regardless of legitimacy of relationship.
Marriages Void by Reason of Public Policy
Beyond incest, other marriages are void for public-policy reasons, including those between:
- Collateral relatives by blood up to the fourth civil degree — this includes first cousins and, for example, uncle-niece/aunt-nephew;
- Step-parents and step-children;
- Parents-in-law and children-in-law;
- The adopting parent and the adopted child, and certain relationships arising from adoption (such as the adopted and a legitimate child of the adopter, or two adopted children of the same adopter); and
- Parties where one killed the other's spouse (or their own spouse) in order to marry the other.
Knowledge Is Irrelevant
An important point: these marriages are void whether or not the parties knew of the impediment. Ignorance of the relationship does not save the marriage. The prohibition rests on the relationship itself and on public policy, not on the parties' awareness.
Consequences
Because the marriage is void:
- There is no valid marriage to speak of, and it can be declared void at any time;
- Property relations are governed by the rules for void marriages (co-ownership rules under the Family Code), not the ordinary regimes; and
- Children's status follows the specific rules the law provides for children of void marriages.
Practical Takeaways
- Incestuous marriages (ascendant-descendant, siblings) are void;
- Marriages between certain relatives (up to fourth civil degree, step- and in-law relations, adopter-adopted) are void by public policy;
- These are void regardless of the parties' knowledge — the relationship alone is the bar.
Frequently Asked Questions
Which marriages are incestuous and void? Marriages between ascendants and descendants of any degree (such as parent and child, grandparent and grandchild) and between brothers and sisters, whether of the full or half blood.
Can first cousins marry in the Philippines? No. Marriages between collateral relatives by blood up to the fourth civil degree, which includes first cousins, are void by reason of public policy.
What other relationships make a marriage void by public policy? Marriages between step-parents and step-children, parents-in-law and children-in-law, an adopter and the adopted (and certain adoption relationships), and where one party killed the other's spouse to marry them.
Does it matter if the parties did not know they were related? No. These marriages are void whether or not the parties knew of the impediment. The prohibition rests on the relationship itself and public policy, not on the parties' awareness.
This commentary is for general informational purposes only and does not constitute legal advice. For guidance specific to your situation, please consult a licensed attorney.
If you have questions about your rights or options under Philippine law, our firm is available to assist. You may reach us via Viber or WhatsApp, call us at 0995 433 5550, or send an email to vivasnobles@gmail.com. We look forward to hearing from you.