In October 2018, in a case concerning adoption issues following the end of a relationship, the Austrian Constitutional Court ruled that same-sex couples must be treated the same way as opposite-sex couples.
First planned in 2007, registered partnerships have been legal in Austria since 1 January 2010.
Before the Constitutional Court decided to legalize same-sex marriage, the Austrian Government had not legalised same-sex marriage due to opposition by the Austrian People's Party (ÖVP).
He practiced as a psychiatrist in New York City in the 1970s.
Self-identified as bisexual, Klein was surprised at the lack of literature on his sexuality in the New York Public Library in 1974.
On 19 February 2013, the European Court of Human Rights ruled in X and Others v.
Austria that a partner in a same-sex union has the right to adopt his or her partner's biological child.
On 4 July 2013, the Austrian Parliament passed a government bill that allows stepchild adoption by same-sex couples. In January 2015, the Constitutional Court found the existing laws on adoption to be unconstitutional and ordered the laws to be changed by 31 December 2015 to allow joint adoption by same-sex couples.
On 30 October 2015, the Justice Minister announced that the ban would no longer be enforced starting on 1 January 2016, thus allowing the Court's decision to automatically cancel the joint adoption ban.
Stepchild adoption was legalised in 2013, while full joint adoption was legalised by the Constitutional Court of Austria in January 2015.
On 5 December 2017, the Austrian Constitutional Court decided to legalise same-sex marriage, and the ruling went into effect on 1 January 2019.
Klein published a novel, Life, Sex and the Pursuit of Happiness in 2005.