both in Kapellen near Antwerp. In November 2003, opponents of same-sex marriage petitioned the Arbitration Court to invalidate the law as unconstitutional. Their main argument held that treating fundamentally different situations the same way violates the equality principle of the Constitution. In October 2004, the Arbitration Court, nowadays known as the Constitutional Court, rejected the request. Subsequent changes Originally, Belgium allowed the marriages of foreign same-sex couples only if their country of origin also allowed these unions. A circulaire by Minister of Justice Laurette Onkelinx (PS) of 23 January 2004, however, permits any couple to marry in Belgium if at least one of the spouses has lived in the country for a minimum of three months. This was codified into the Code of Private International Law, which took effect on 1 October 2004. The same-sex marriage law did not permit adoption by same-sex partners, and as birth within a same-sex marriage did not imply affiliation, the same-sex spouse of the biological parent had no way to become the legal parent. A proposal to permit adoption was approved 77–62 (with 7 abstentions) by the Chamber of Representatives on 1 December 2005, and 34–33 (with 2 abstentions) by the Senate on 20 April 2006. It received royal assent on 18 May and went into force on 30 June 2006. A legal inequality compared to heterosexual couples still existed with regards to children: the husband of the biological mother is automatically legally recognised as the father (by article 135 of the Civil Code), but this was not the case in a same-sex union for the wife of the mother. To be recognised as the co-mother, she had to complete an adoption procedure. This accounted for the large majority of adoption cases in Belgium. The Di Rupo Government promised to fix this, and in 2014, as the Netherlands had recently passed similar legislation, LGBT organisations pressured the government about their promise. Subsequently, legislators worked to agree on a solution. A bill to this end was approved by the Senate on 3 April 2014 on a 48–2 vote (with one abstention), and by the Chamber of Representatives on 23 April on a 114–10 vote (with one abstention). The bill received royal assent by King Philippe of Belgium on 5 May and went into effect on 1 January 2015. Since this change, female same-sex couples are treated equally to heterosexual couples: the co-mother married to the