Basically, without directly saying it, the court is taking the legal age of consent to mean both a calendar date and a 'mental capacity age'.
"A man with an IQ of 48 has been ordered to stop having sex by a High Court judge.
Known only as Alan, the 41-year-old was in a relationship with a man he lived with and said he wanted it to continue.
The authority said that his moderate learning disability and IQ of just 48 - the average is 100 - meant he did not understand what he was doing.
Despite his fears for interfering in a person's sex life, he agreed that he did not have the mental capacity to know about the health risks and should be banned from having sex.
His council will now monitor him closely to make sure he doesn't breach the order.
Justice Mostyn said: 'Alan does not have the capacity to consent to and engage in sexual relations."