The Marriage Act 1961 (Cth) is an Act of the Parliament of Australia which regulates marriage in Australia. Since its passage in 1961, it has been amended on numerous occasions and applies uniformly throughout Australia (including its external territories); and any law made by a state or territory inconsistent with the Act is invalid. The Act was made pursuant to power granted to the federal parliament under s.51(xxi) of the Australian Constitution. Although the federal parliament was given the power to pass laws about marriage at federation in 1901, it did not use this power until the adoption of the Act, while before 1961, each Australian state and territory had its own marriage laws. The Act recognises only marriages of two people and does not recognise any other forms of union, including traditional Aboriginal unions. An amendment to the Act to legalise same-sex marriage passed into law on 8 December 2017. The Family Law Act 1975 treats de facto relationships and polygamous marriages as marriages for the purpose of recognising the rights of parties at a breakup. Since 2009, the Family Law Act 2009 has also recognised the property rights of each partner of de facto relationships on separation. The Act Marriageable age Part II (s.10-21) deals with the marriageable age and the marriage of minors. In the original 1961 Act, marriageable age was set at 16 for females and 18 for males. However, under section 12 of the original 1961 Act a female 14 or 15 years or a male 16 or 17 years could apply to the court for permission to marry. The marriageable age was equalised in 1991 by the Sex Discrimination Amendment Act 1991, which raised the marriageable age of females to 18. The marriage of a person aged 16 or 17 to another aged over 18 is permitted in "unusual and exceptional circumstances", which requires the consent of the younger person's parents and authorisation by a court. Prior to the 1991 changes, the "unusual and exceptional circumstances" procedures applied to a girl aged 14 or 15 (wanting to marry a male aged 18 or above) or a male aged 16 or 17 (wanting to marry a female aged 16 or above). For many years, courts have refused to accept a minor's pregnancy as a pressing consideration in deciding whether to allow an early marriage. Void marriages Part III entitled "void marriages" establishes the circumstances in