Japan's civil law and family registration law provisions are based on marriage between a man and a woman and the privileges that result from matrimony, including inheritance rights, tax benefits and joint custody of children, are only granted to heterosexual couples. Japan remains the only Group of Seven industrialized country that has not legalized same-sex marriage or civil unions, despite lobbying from the LGBT community and its supporters. In total, six lawsuits contesting the lack of legal recognition of same-sex marriage were filed at five district courts across the country, with one ruling it is constitutional, two unconstitutional, and three ruling that it is "in a state of unconstitutionality" -- a term seen as a call for the Diet to address the law's inconsistency with the Constitution.