Under Indonesian law, a biological father who has a child born out of a valid marriage may still have a legal relationship with that child. However, a biological relationship does not automatically confer all the rights and authorities of a father born of a valid marriage.

The primary legal basis is as follows.


1. Law No. 1 of 1974 on Marriage

As amended by Law No. 16 of 2019.

Article 43(1), as interpreted in accordance with Constitutional Court Decision No. 46/PUU-VIII/2010, essentially states:

A child born out of wedlock has a civil relationship with the mother and the mother’s family, as well as with the man who, based on science and technology and/or other evidence admissible under the law, can be proven to have a blood relationship as the child’s father, including a civil relationship with the father’s family.


2. Constitutional Court Decision No. 46/PUU-VIII/2010

This decision provides legal protection for children born out of wedlock.

Implications:

The biological relationship between a father and a child can be proven through a DNA test.

The biological father may have a civil relationship with the child.

The child may receive protection of civil rights from his or her biological father.

Civil relations may extend to the biological father’s family.


3. Civil Code (KUHPerdata)

Article 280 of the Civil Code: The acknowledgment of a child born out of wedlock gives rise to a civil relationship between the child and his or her father or mother.

Article 281 of the Civil Code: The acknowledgment of a child may be made through an authentic instrument in accordance with the provisions of the law.

These provisions are particularly relevant in civil law systems that recognize the mechanism of child acknowledgment.


4. Child Protection Law

Law No. 23 of 2002, as amended by Law No. 35 of 2014.

Article 7, paragraph (1): Every child has the right to know his or her parents and to be raised and cared for by his or her own parents.

Article 14: This article governs a child’s right to receive care from his or her parents, including protection in the event of separation.


5. Compilation of Islamic Law (KHI)

Specifically for Muslims:

Article 100 of the KHI states that a child born out of wedlock has a blood relationship only with the mother and her family.

Therefore, a distinction must be made between blood relationships under Islamic law and civil relationships with the biological father, based on Constitutional Court Decision No. 46/PUU-VIII/2010.


Important: A Constitutional Court ruling does not automatically grant custody or parental authority to the biological father. Custody must be determined based on the best interests of the child and applicable legal provisions. 

Legal Conclusion

A biological father who is not legally married to the child’s mother does not automatically lose all of his civil rights regarding the child. Based on Constitutional Court Decision No. 46/PUU-VIII/2010, a blood relationship can serve as the basis for the establishment of civil rights between the biological father and the child, provided it can be proven in accordance with the law.

However, the biological father’s rights must be distinguished from custody rights, guardianship rights, rights of descent, and inheritance rights, as each carries its own distinct legal consequences.