In an ideal world, sportsmen would never cast aspersions on the morals of their opponents' female relatives, writes Frank McNally.
But this is not an ideal world, and insulting mothers, sisters, wives, and girlfriends remains a popular tactic for unsettling the opposition. So much so, that it seems like a failure of coaching whenever a player falls for the ruse and gets himself sent off for defending a woman's honour.
Curiously, among the set of female relatives an average man is likely to have, only his grandmother is considered above this kind of abuse. Not only is she rarely accused of moral laxity, she often has exaggerated athletic abilities attributed to her. Miss an open goal, say, and chances are even your own team-mates will suggest that "your granny would have scored that with her eyes closed".
The female-relative-insult gambit is almost too obvious for coaching. Advising a player that his sister's social life may feature in verbal exchanges is like breaking the news that he is more likely to be tackled while in possession of the ball. And even if the subject is dealt with in team talks, there is no guarantee that an opponent's jibe will not unleash the mediaeval knight that lurks within every man, avenging sword at the ready.
Male ideas about honour can be complex. But a good starting point from which to explore them is the famous Irish duelling code, devised by lawyers meeting on the fringes of the Clonmel Assizes of 1777. Like a piece of consolidating legislation, the code was clearly aimed at tidying up the rules by which gentlemen were allowed to kill and maim each other over matters of honour; and it is a highly legalistic document.
Among other things, it states that once duellists have reached the place appointed, they should make an honest attempt to hit their targets. Firing in the air is "children's play", it says, adding sniffily: "The challenger ought not to have challenged without receiving offence; and the challenged ought, if he gave offence, to have made an apology before[ hand]." Inevitably, many duels were over women, and Articles 10 and 11 of the code make clear how serious such matters were.
Article 10: "Any insult to a lady under a gentleman's care or protection [ is] to be considered as, by one degree, a greater offence than if given to the gentleman personally, and to be regulated accordingly."
Article 11: "Offences originating or accruing from the support of ladies' reputations [ are] to be considered as less unjustifiable than others of the same class and as admitting of slighter apologies by the aggressor - this to be determined by the circumstances of the case, but always favourable to the lady." Seen in historical context, therefore, the flailing fists of Trevor Brennan, as he charged into a crowd of Ulster rugby supporters at the weekend after alleged comments about his mother, represent the march of civilisation.
There is still a big conflict over what exactly provoked his attack. The player says Ulster fans chanted that his mother was a "whore", whereas his victim claims he insulted only Brennan's pub, which he admits describing as - and I quote - "below par".
In all my years attending football and rugby games, I have never heard the term "below par" deployed to abuse an opposition player. Then again, many rugby supporters have been to very good schools, so it must be possible that this is what the man said. Whatever the truth of it, Brennan's attack was an over-reaction. But the mere possibility that his mother was impugned would still probably secure his acquittal by a jury at the Clonmel Assizes.
If the duelling code were being updated now to cover sports, it would have to admit of different levels of offence regarding female relatives. Most sportsmen would agree than an insult to one's mother is to be considered, by one degree, more serious than an insult to one's sister, and to be regulated accordingly. Indeed, I suspect the widespread sympathy for Zinedine Zidane after last year's World Cup was based on a popular assumption that his mother was central to whatever Marco Materazzi said to him.
That such a gifted player had thrown away the climax of his glittering career by responding as he did suggested an awe-inspiring breach by Materazzi of the male code of honour. And that the exact nature of the terrible insult was not exposed for two months afterwards lent it a status once reserved for the third secret of Fatima.
When the shame-faced Italian finally revealed the truth - that he had responded to Zidane's sarcastic offer of a shirt exchange by asking for his "sister" instead - it was an anti-climax. No doubt this was the cleaned-up version. But Materazzi's claim that he didn't even know if Zidane had sisters rang true. Sadly, throwing such a casual and unresearched jibe at an opponent is as standard a move in football as having a speculative long-range shot to see of the keeper is dodgy.
I hope there are no coaches out there whose intelligence-gathering on the opposition extends to finding out if any of them are related to lap-dancers. Either way, a player's sensitivity on behalf of his female relations is a big disadvantage in team sports, and may be exploited.
If you're vulnerable to this sort of thing, it would be advisable to ensure that all your sisters are nuns. If your mother's a nun, though, you're in trouble.