Section 216 of our Queensland Criminal Code makes it unlawful (i.e. a criminal offence) for any person to have intimate relations (i.e. sex!) with another person who has ‘impairment of the mind’, which is defined broadly in the Criminal Code and includes any person with an intellectual, psychiatric, cognitive or neurological impairment that results in a substantial reduction in that person’s capacity for communication, social interaction or learning, and that person needing support.
That’s long-winded, so, for example, someone such as Stephen Hawking likely would have fit the definition, as would many people who have cerebral palsy that makes communication difficult without support, or intellectual disability.
Notice that there’s nothing there about decision-making capacity. Parliament framed section 216 on the assumption that if you fit the definition you are not capable of making a decision about whether you can/want to have sex. Consent, or not, does not matter.
The provision is discriminatory. It’s less favourable to many people with disability, and indeed many people who fit the definition of ‘person who has impairment of the mind’ are in relationships, including marriages, to other people who fit this definition.