The J.Y. Interpretation No. 748, while stating that same-sex couples may file applications to register the marriage if the relevant legislation fails to be enacted within two years, it didn’t specify how the said couples should do if they wish to have any offspring after such registration. Since the current parent-child relationship is based on the structure of opposite-sex marriage, it’ll be controversial if the “child presumed to be born in wedlock”, “biological father’s acknowledgment” and “post-marital legitimization” systems under the current Civil Code also apply to same-sex couples’ parent-child relationships and in particular, how to establish the parent-child relationship with the said couple’s existing children, how shall the court handle the application for adoption after May 24, 2019, and what legislative approaches shall be taken in the future. All of the above are topics that this article will discuss.