Children of "siri" marriages are deemed at a disadvantage under the mariage Act, Law No. 1 Year 1974, as they ae regarded as illegitimate under state law. As a legal consequence, siri children do not derive civil rights, particulary inheritance, from their father and the father's family. This 2012 ruling of the Constitutional Courth granting judicial review of Article 43 paragraph (1)of the Marriage Act has effectively amended the said law. Siri children, including those born from mat'ah marriages, common law unions and adulterous relationships, are now given equal right accorded to legitimate children if blood ties with the father is proven or established by science and technologi and/or other evidence under the law. This paper discussed the implications of this ruling on the civil rights of illegitimate children flowing from their parental relationship with their biological father.