Below is a comprehensive discussion of Nullity of Marriage and Legitimacy of Children under Philippine law, primarily guided by the Family Code of the Philippines (Executive Order No. 209, as amended). This article covers the legal definitions, grounds, processes, and effects on children when a marriage is declared void ab initio or voidable (annullable), including the important principle that “children conceived or born before the judgment of nullity or annulment becomes final are deemed legitimate” (with certain notable exceptions). Although this discussion is extensive, it is not legal advice. When dealing with an actual or potential case, always consult a licensed Philippine attorney.

1. Legal Framework

Family Code of the Philippines (E.O. No. 209, as amended)
- Governs marriage, property relations, and family matters, including legitimacy of children.
- Effective since August 3, 1988, superseding relevant portions of the New Civil Code on family law.
Relevant Provisions
- Articles 35–38, 40–44: Enumerate grounds for declaring a marriage void (nullity of marriage).
- Articles 45–47: Enumerate grounds for annulling (voidable) marriages.
- Article 36: Psychological incapacity as a ground for declaration of nullity.
- Articles 49–52: Effects of nullity, particularly in terms of liquidation of property and ramifications for subsequent marriages.
- Articles 54, 164–182: Address legitimacy, illegitimacy, legitimation, and recognition of children.

2. Definitions and Distinctions

2.1. Nullity of Marriage (Void ab initio)

A void (null) marriage is considered nonexistent from the very beginning—“void ab initio.”
When a court issues a Declaration of Nullity of Marriage, the legal effect is that no valid marriage ever existed between the parties.
Although the Family Code clarifies this through judicial declaration, for practical purposes one must still secure a court decision (a final judgment) confirming the marriage’s nullity before one can legally remarry or assert legal rights that flow from the null status of the marriage.

2.2. Annulment of Marriage (Voidable)

A voidable marriage is considered valid and existing until it is annulled by final judgment.
Grounds for voidable marriages often relate to defects in the parties’ consent (e.g., lack of parental consent for minors, fraud, force, intimidation, mental incapacity at the time of marriage).
Unlike a void marriage, a voidable marriage is deemed valid up to the time it is annulled by the court.

2.3. Key Difference

Void marriages never produce legal effects from the start (except as to the legitimacy status of children under specific provisions).
Voidable marriages are valid until annulled and can produce normal legal effects during their existence (e.g., property regime, presumptive legitimacy of children).

3. Grounds for Declaring a Marriage Void (Nullity of Marriage)

The Family Code enumerates several grounds under which a marriage is deemed void ab initio:

Absence of Essential or Formal Requisites (Article 35)
- No valid marriage license (unless exempted by law, e.g., marriages of exceptional character).
- Contracted by a party below 18 years of age (even with parental consent).
- Solemnized by someone not authorized to perform marriages (except if either or both parties believed in good faith that the solemnizing officer had authority).
- Bigamous or polygamous marriages not falling under exceptions provided by law.
- Mistake as to the identity of one of the parties.
- Subsequent marriages that fail to comply with prescribed procedures after a judicial declaration of nullity or presumptive death of a spouse (Articles 40–41, 52–53).
Psychological Incapacity (Article 36)
- Either spouse is psychologically incapacitated to comply with the essential marital obligations.
- Ground must refer to an incurable, grave, or serious psychological condition existing at the time of the marriage.
- Jurisprudence (e.g., Republic v. Molina, Santos v. Bedia-Santos) has established guidelines for proving psychological incapacity.
Incestuous Marriages (Article 37)
- Marriages between ascendants and descendants of any degree.
- Marriages between brothers and sisters (whether full or half-blood).
Marriages Against Public Policy (Article 38)
- Between collateral blood relatives up to the fourth civil degree.
- Between step-parents and step-children, parents-in-law and children-in-law, etc. (as enumerated under Art. 38).
Other Statutory Grounds
- Article 40: Prior existing marriage. A second or subsequent marriage without the judicial declaration of nullity of a prior marriage is void.
- Articles 52–53: Failure to record a final judgment of nullity and comply with liquidation/distribution of properties before contracting a subsequent marriage also results in the second marriage being void.

4. Grounds for Annulling a Marriage (Voidable)

Though the main focus is on the nullity of marriage, it is helpful to see how annulment relates to children’s legitimacy:

Lack of parental consent (Article 45[a]) when either party was between 18 and 21 at the time of marriage.
Insanity (Article 45[b]) of one party, existing at the time of marriage.
Fraud (Article 45[c]), such as concealment of pregnancy by another man, sexually transmissible disease, or conviction for a crime, if it directly induced the other party to give consent.
Force, intimidation, or undue influence (Article 45[d]).
Impotence (Article 45[e]), existing at the time of marriage and continuing.
Serious and incurable sexually transmissible disease (Article 45[f]) existing at the time of marriage.

A voidable marriage remains valid until there is a final judgment annulling it. Children conceived or born within such a marriage, before final judgment, are generally deemed legitimate.

5. Legitimacy of Children: General Principles

5.1. Presumption of Legitimacy

Under Philippine law:

A child born or conceived during the valid marriage of the parents is presumed legitimate (Article 164, Family Code).
Even where the marriage is subsequently declared void or voidable, there are protective provisions for the child’s legitimacy status.

5.2. Children Born from Void Marriages

Article 54 of the Family Code states that children “conceived or born before the judgment of absolute nullity of the marriage under Article 36 or the judgment of annulment is final, shall be considered legitimate.” This is often referred to when discussing psychological incapacity (Article 36) or when a marriage is annulled (voidable). Hence:

When the ground for nullity is Article 36 (psychological incapacity):
Children conceived or born before the final judgment are deemed legitimate. The law aims to protect the children from the stigma and negative consequences of a void marriage.
When a marriage is annulled (voidable marriage):
Children conceived or born while the marriage was still presumed valid are considered legitimate.

5.3. Children Born from Other Types of Void Marriages

If the marriage is void for reasons not covered by Article 36 (for example, bigamous or incestuous marriages), the Family Code does not automatically extend legitimate status to the children. In these instances, they will typically be considered illegitimate unless other legal grounds for legitimate status apply. However, the child retains certain rights (e.g., right to support) from biological parents, though the child’s status would not be that of a legitimate child.

6. Legal Effects of Nullity on Children

Legitimate Status (Article 54)
- As reiterated, if the marriage is declared void based on psychological incapacity (Art. 36) or if it is annulled (voidable), children remain legitimate if conceived or born before the judgment became final.
Illegitimate Status
- If the marriage was void due to reasons other than psychological incapacity (e.g., incest, bigamy, violation of Articles 35, 37, 38), children’s status is generally illegitimate.
- They are, however, still entitled to support, inheritance rights (though fewer than legitimate children), and parental acknowledgment.
Use of Surname
- Legitimate children ordinarily carry the father’s surname.
- Illegitimate children are usually registered under the mother’s surname unless recognized or acknowledged by the father under procedures provided by law (RA 9255 and subsequent regulations).
Inheritance Rights
- Legitimate children have full inheritance rights to the estates of both parents.
- Illegitimate children (if the marriage is void for reasons not covered by Article 36) are still compulsory heirs but are generally entitled to only half the share of legitimate children.

7. Procedural Aspects: Declaration of Nullity

Filing a Petition
- An interested party files a petition for Declaration of Nullity of Marriage (for void marriages) or Annulment of Marriage (for voidable marriages) before the Regional Trial Court (Family Court) with jurisdiction over the petitioner or respondent’s residence.
Proof and Evidentiary Requirements
- The burden is on the petitioner to prove the existence of any ground for nullity or annulment. For psychological incapacity, expert testimony (psychologists/psychiatrists) and detailed proof are typically presented.
Fiscal’s / Prosecutor’s Investigation
- To prevent collusion, the public prosecutor or fiscal is mandated to appear and ensure the parties do not collude to secure a nullity or annulment decree.
Finality of Judgment
- Once a decision is rendered, there is a 15-day waiting period (extendable if a motion for reconsideration or appeal is filed). Only after the decision becomes final can the parties remarry or record the judgment in the civil registry.
- For children’s legitimacy status under Article 54, the relevant point is whether they were conceived or born before that final judgment.
Recording Requirements
- Under Articles 52–53 of the Family Code, after a final judgment of nullity, the parties must register the decree in the Local Civil Registry where the marriage was recorded and in the National Statistics Office (now Philippine Statistics Authority).
- For subsequent marriages to be valid, the liquidation and distribution of properties from the previous union must also be completed and recorded.

8. Notable Jurisprudence

Republic v. Court of Appeals and Molina (G.R. No. 108763, February 13, 1997)
- Laid down the guidelines (the “Molina Guidelines”) for proving psychological incapacity.
- Stressed that the incapacity must be psychological, existing at the time of the marriage, and deemed incurable or gravely serious.
Santos v. Court of Appeals (G.R. No. 112019, January 4, 1995)
- First major Supreme Court decision clarifying “psychological incapacity” under Article 36.
Valdes v. RTC, Branch 102, Quezon City (G.R. No. 122749, May 3, 2006)
- Reinforced that the burden of proof is on the petitioner and that courts must carefully assess the evidence of psychological incapacity.
Subsequent Clarifications
- The Supreme Court has, over time, become somewhat more flexible in applying Article 36, emphasizing that each case must be decided on its own facts and that mental illness per se is not always required; incapacity to fulfill basic marital obligations is key.

9. Practical Implications and Recommendations

Children’s Status
- Parents should be mindful that, in general, if a marriage is declared void for reasons other than psychological incapacity (especially incestuous or bigamous marriages), children born in that marriage may be classified as illegitimate.
- For an annulment or a declaration of nullity under Article 36, children remain legitimate if born or conceived before the finality of the judgment.
Rights of Illegitimate Children
- Illegitimate children are entitled to support and a share in inheritance (albeit half the share of legitimate children).
- They are still recognized by law as children of their biological parents, but their status differs from legitimate children in matters like surname use and inheritance portions.
Legal Documentation
- Once the nullity or annulment decree becomes final, ensuring proper documentation—i.e., annotation in the civil registry (both Local and Philippine Statistics Authority)—is crucial.
- This step is needed before remarrying and to clarify the status of children and property relations.
Consultation with Legal Counsel
- Because nullity cases (especially psychological incapacity petitions) can be complex and evidence-intensive, professional legal counsel is essential.
- Each case has unique nuances; the guidance of a licensed Philippine attorney is critical to navigate case strategy, evidence gathering, and compliance with procedural rules.

10. Conclusion

In the Philippine legal system, nullity of marriage underscores the principle that certain defects render a marriage void from the beginning, while annulment addresses grounds that make a marriage voidable, even if it initially appears valid. Crucially, the Family Code balances the sanctity of marriage with the best interests of the child, providing that children generally retain legitimacy (or certain rights) if born or conceived before a marriage is declared void under specific grounds (particularly Article 36) or while a voidable marriage subsists.

In practice, safeguarding children’s legitimacy and rights to support and inheritance has been a guiding aim of Philippine family law. However, the grounds and procedural nuances for nullity or annulment can be intricate. Anyone facing these questions should engage legal counsel and proceed with a thorough understanding of both substantive and procedural requirements.