It took a trial and two appeals. But now Italians know where they stand.

They may think it. They may mutter it. But, on pain of a hefty fine, they must not say it.

With all the solemnity on which it can draw, Italy's highest appeals court has ruled it is a crime to utter the words: "You don't have the balls." And for reasons that are potentially as controversial as the judgment itself.

The court decided the phrase should be outlawed, not so much because it cast doubt on the offended party's virility, but because it implied a "lack of determination, competence and consistency – virtues which, rightly or wrongly, continue to be regarded as suggestive of the male sex'.

In this instance, the offended party was a lawyer from the southern city of Potenza. The existence of his procreative organs was called into question by his cousin, a justice of the peace, in a public courthouse row.

The judges at the trial ruled for the lawyer. But the justice of the peace took his case to appeal, where his counsel persuaded the court that the accusation levelled at him was a load of, well, nonsense.

The judges declared that the claim regarding their learned friend's allegedly missing testicles could not be regarded as offensive because it had been levelled "in the context of a family dispute". Undaunted, the offended party appealed to Rome where it was argued, on his behalf in a hearing on 26 June, that while it was acceptable to say, for example, "don't break my balls", it was unacceptable to claim that "you don't possess the attributes – in other words, you are worth less than other men."

It will be up to a lower court to decide on the size of the fine.