In the Philippine legal system, the dissolution of a marriage through annulment or a declaration of absolute nullity carries significant implications for the status and successional rights of the children involved. While the marriage itself may be set aside, the law provides specific safeguards to ensure that the rights of the offspring—particularly regarding their legitimacy and inheritance—are preserved or clearly defined.

1. Determination of Status: Legitimate vs. Illegitimate

Under the Family Code of the Philippines, the status of children born of a marriage that is subsequently set aside depends largely on the specific ground used to dissolve the union.

Annulment (Voidable Marriages): If a marriage is "voidable" (valid until annulled under Article 45), children conceived or born before the judgment of annulment has become final and executory are considered legitimate.
Declaration of Absolute Nullity (Void Marriages): Generally, a void marriage (Article 35, 36, 52, 53) is considered to have never existed. However, the law makes two critical exceptions where the children remain legitimate:

Children born of marriages declared void under Article 36 (Psychological Incapacity).
Children born of marriages declared void under Article 53 (Failure to record the partition and distribution of properties from a previous marriage).

Illegitimate Status: Children born of other void marriages (e.g., incestuous marriages or bigamous marriages not falling under Article 41) are generally classified as illegitimate.

2. General Principles of Inheritance

The Civil Code of the Philippines dictates that the rights to the succession are transmitted from the moment of the death of the decedent. Inheritance rights are primarily determined by the child's status at the time of the parent's death.

Legitimate Children

Children of annulled marriages who retain their legitimate status are entitled to a legitime, which is the part of the testator's property that they cannot be deprived of without a legal cause (disinheritance).

The Share: The legitime of legitimate children consists of one-half (1/2) of the hereditary estate of the father and of the mother.
Concurrent Successors: If they concur with a surviving spouse, the spouse is entitled to a share equal to the legitime of each of the legitimate children.

Illegitimate Children

If the marriage was void ab initio (and does not fall under the exceptions of Article 36 or 53), the children are illegitimate.

The Share: Under Article 176 of the Family Code, the legitime of each illegitimate child consists of one-half (1/2) of the legitime of a legitimate child.
Right to Inherit: Despite the "illegitimate" label, these children possess full successional rights to the estate of their parents, provided their filiation is duly proven through the record of birth, a final judgment, or an admission of filiation in a public document or private handwritten instrument.

3. The Requirement of Partition and Delivery (Article 50 & 51)

A unique feature of Philippine law regarding annulment and declarations of nullity is the protection of the children's "future" inheritance.

Under Article 50 and 51 of the Family Code, in the partition of the properties of the dissolved marriage, the delivery of the presumptive legitimes of all common children must be ensured.

Presumptive Legitime: This is the portion of the parents' current property that would correspond to the children's inheritance if the parents had died at the time of the annulment.
Registration Requirement: The final judgment of annulment, the partition of properties, and the delivery of these presumptive legitimes must be recorded in the appropriate Registry of Deeds and Civil Registry.
Consequence of Non-compliance: Failure to comply with this recording requirement means that the disposition of property will not affect third parties, and importantly, it creates a legal impediment for either parent to remarry validly.

4. Right to the Surname

Inheritance rights are often linked to the legal recognition of the parent-child bond, which is symbolized by the surname.

Legitimate Children: They have the right to bear the surnames of the father and the mother.
Illegitimate Children: Under Republic Act No. 9255, illegitimate children may use the surname of their father if their filiation has been expressly recognized by the father through the record of birth or when an admission in a public document or private handwritten instrument is made. This recognition is often the foundational evidence used to claim inheritance later.

5. Summary of Rights

The law treats children of annulled marriages with significant favor to prevent them from suffering due to the legal errors or incapacities of their parents.

Child's Status	Source of Status	Legitime Share
Legitimate	Voidable (Art. 45), Psych. Incapacity (Art. 36), or Art. 53	1/2 of the estate (divided among all legitimate children)
Illegitimate	Other Void Marriages (e.g., Art. 35, 37, 38)	1/2 of the share of a legitimate child

In conclusion, an annulment does not sever the bond of filiation. Whether legitimate or illegitimate, children of dissolved marriages remain compulsory heirs of their parents. The primary difference lies in the proportion of the estate they receive, with the law prioritizing the protection of "legitimate" status in the most common grounds for marital dissolution.