<![CDATA[The development of Assisted Reproductive Technology (ART), particularly surrogacy, has created new forms of kinship that are not explicitly addressed in classical Islamic family law. One such relationship is that of gestational siblings, namely children born from the same gestational mother but without a genetic connection. This phenomenon raises legal questions concerning lineage, inheritance, and, more importantly, the permissibility of marriage between gestational siblings. This study aims to examine the legal status of such marriages from the perspectives of Sunni and Imāmī Shīʿī jurisprudence, assess their relevance within the Indonesian legal system, and formulate an appropriate ius constituendum model in response to advances in reproductive technology. This research employs a normative legal method using statutory, conceptual, comparative, and case approaches. The analysis is conducted through comparative legal analysis and prescriptive legal reasoning. The findings show that Sunni jurisprudence generally considers genetic affiliation the primary basis for determining lineage and marriage prohibitions; therefore, gestational siblings are not regarded as legally prohibited from marrying each other. In contrast, certain Imāmī Shīʿī views recognize the legal significance of gestational motherhood, potentially extending marriage prohibitions beyond purely genetic relationships. The study also finds that Indonesian law has not specifically regulated the status of gestational siblings or its implications for marriage restrictions. Accordingly, this article proposes a Hybrid Model that integrates both genetic and gestational relationships as the basis for marriage prohibitions in order to strengthen legal certainty, lineage protection, and family welfare.]]>
