Many of Sachs's best-known judgments are on discrimination law. He was the main author of the majority judgment in "Prinsloo v Van der Linde", which established the connection between the right to equality and dignity. He was the author of the Court's majority judgment in "Minister of Home Affairs v Fourie", in which the Court declared unconstitutional South Africa's statute defining marriage to be between one man and one woman. O'Regan J strongly criticised Sachs for referring the regulation of same-sex marriage to Parliament rather than providing immediate relief. The two had, in 2002, written a joint dissent which held that the criminalisation of sex work (and not its solicitation) unfairly discriminates on the basis of gender and is therefore unconstitutional.