The show is over for Kaya FM's controversial shock jock, Phat Joe.

The motormouth breakfast show host, whose real name is Mojota Khambule, was fired on Thursday after his three-week suspension for insensitive comments about gold medallist Caster Semenya.

It started out as a single question, during his show, whether Semenya had ever had her period. Khambule then referred to Semenya as having "internal testicles", based on an article on leaked sex test results in an Australian newspaper.

When callers got uptight, Khambule retorted: "What is the difference between testes and testicles? Let's say she has testes... Does it mean she is a man or a woman? She is either a natural phenomenon, or something is wrong and something should be fixed."

Kaya FM said it had received "an overwhelming number" of calls, e-mails, SMSes and Facebook messages, as well as complaints to the Broadcasting Complaints Commission of South Africa.

The station said Khambule's statements threatened its relationship with listeners and advertisers.

Khambule said last night: "They felt well within their rights... I'm going to keep my opinion to myself."

The Freedom of Expression Institute's Melissa Moore said: "On the face of it, it is not a prohibited form of speech. But you would have to... weigh up his freedom of expression against (Semenya's) right to privacy."