In the context of the Philippine legal framework, paternity and filiation are crucial elements within Family Law, specifically regulated by the Family Code of the Philippines (Executive Order No. 209, as amended). These concepts govern the relationship between parents and children and have significant implications for the rights, duties, and legal status of both parties. The Family Code provides comprehensive rules to address issues related to paternity and filiation, establishing the legal basis for determining a child’s parentage and the corresponding rights that follow.

1. Types of Filiation

Under the Family Code, filiation may be classified into legitimate, illegitimate, and legitimated children:

Legitimate Children: These are children conceived or born during a valid marriage, or within a marriage that is voidable but not yet annulled. Legitimate children are entitled to bear the surname of their father and to receive support, parental authority, and inheritance rights in accordance with Article 174 of the Family Code.
Illegitimate Children: These are children conceived and born outside a valid marriage, and they are entitled to support and inheritance rights, albeit in lesser amounts than those granted to legitimate children. Illegitimate children bear the surname of their mother unless recognized by their father, as per Republic Act No. 9255, which amended Article 176 of the Family Code.
Legitimated Children: If parents of an illegitimate child subsequently marry, the child may become legitimated by operation of law, provided the parents had no legal impediment to marry at the time of the child's conception (Article 177, Family Code).

2. Proof of Filiation

To establish filiation, especially for legitimate or illegitimate children, the Family Code outlines specific ways to prove filiation:

Primary Evidence:
- The child’s record of birth or a baptismal certificate can serve as primary evidence of filiation.
- The parent’s admission of filiation in public or private documents, including personal letters, can also be considered proof.
Secondary Evidence:
- If primary documents are unavailable, acts showing an “open and continuous possession of the status of a legitimate child” may be acceptable. This includes acts where the parent treats the child as legitimate, introduces them as such to the public, and provides them with support and guidance.
- Other testimonies of witnesses who can attest to the parent-child relationship are also allowed in the absence of primary evidence.

For illegitimate children, the same rules apply, but proof of filiation is even more essential because legal rights such as inheritance depend upon establishing a recognized relationship between the child and the parent.

3. Presumption of Legitimacy

The Family Code provides a presumption of legitimacy, meaning that children conceived or born during the marriage of their parents are presumed legitimate unless proven otherwise. This presumption arises in specific situations:

If a child is born within 300 days after the termination of a marriage (due to death, annulment, etc.), the child is presumed to be the legitimate offspring of the mother’s last husband (Article 168, Family Code).
In cases where the mother remarries shortly after the death of her previous husband and gives birth, the child’s legitimacy is determined by the legal concept of 300 days, which presumes the child to be of the previous husband if born within 300 days.

4. Action for Recognition and Disavowal of Paternity

a) Action for Recognition of Paternity

An illegitimate child or the mother may file an action to compel a man to recognize the child as his. Under Article 172 of the Family Code, if there is no voluntary acknowledgment, the following may establish paternity:

Open and continuous possession of the status of a legitimate or illegitimate child, as explained previously.
The father’s public or private admission of paternity.

This action must generally be filed during the father’s lifetime, as posthumous recognition can be challenging.

b) Action for Disavowal of Paternity

A legitimate child’s presumed father may file a disavowal action to challenge the child’s legitimacy. Such an action must be based on evidence that the child could not possibly be his, such as proof of non-access (e.g., absence or impotency) at the time of conception. This action must be filed within one year from the time the husband learns of the birth of the child (Article 170, Family Code).

5. Rights of Children Based on Filiation

The rights granted to a child vary based on whether the child is legitimate, illegitimate, or legitimated. Generally, these include:

Right to Support: Both legitimate and illegitimate children are entitled to support from their parents, but the share of illegitimate children is typically half of what a legitimate child would receive (Article 176).
Inheritance Rights: Legitimate children have a right to inherit from both parents, while illegitimate children are entitled to half of the share that legitimate children would receive. Legitimated children enjoy inheritance rights similar to those of legitimate children (Article 887, Civil Code).
Use of Surname: Legitimate children use the surname of their father. Illegitimate children use the surname of their mother unless recognized by the father, in which case they may adopt his surname (Republic Act No. 9255).

6. Implications of Paternity and Filiation on Succession

In the context of succession, filiation determines inheritance rights:

Legitimate children inherit equally from their parents and enjoy rights to compulsory heirship, meaning they cannot be entirely disinherited without valid cause.
Illegitimate children, as “compulsory heirs” under Article 887 of the Civil Code, also have inheritance rights but receive only half the share of legitimate children. However, this right to inherit is absolute once filiation is proven.

The law prioritizes these distinctions in the distribution of the estate, making proof of filiation a central element in the resolution of inheritance cases.

7. Additional Legal Provisions and Remedies

a) DNA Testing

In cases where the child’s filiation is questioned or unclear, DNA testing has become a legally accepted means of establishing or disproving paternity. Philippine courts have admitted DNA evidence, especially in cases where primary and secondary evidence of filiation are insufficient.

b) Adoption and Legitimation of Illegitimate Children

Illegitimate children may be legitimated by subsequent marriage of their parents, provided there was no legal impediment at the time of conception. Through adoption, a child gains rights akin to those of a legitimate child, such as inheritance rights and the right to use the surname of the adopting parent(s).

Conclusion

Paternity and filiation are essential components in the Family Code of the Philippines, with laws structured to safeguard the interests of both parents and children. Filiation affects various legal rights, from support and inheritance to the right to a surname, and is therefore crucial in family law matters. The processes of establishing and contesting paternity and filiation are governed by strict rules to ensure fairness, protect family integrity, and uphold the child’s best interests.