STORY: Japan is the only G7 nation that does not allow same-sex marriage, and its constitution defines marriage as based on "the mutual consent of both sexes.

The ruling party of Prime Minister Fumio Kishida has disclosed no plans yet to review the matter or propose legislation, though several senior members support same-sex marriage.

Wednesday's ruling by the Tokyo district court said that while the ban was constitutional, the absence of a legal system to protect same-sex families is an infringement of their human rights.