The granny rule has been traditionally been kind to Ireland but the case of Jack Grealish demonstrates how fragile a strategy it can be in developing elite players.
Here, we summarise the cases where the FIFA rules have benefited Ireland, situations in which it hasn't worked out in our favour and those with eligibility still undecided on their permanent international future.
Despite declaring for Ireland at 15, expressing a wish to honour his late grandfather from Donegal, Paddy Coyle, the Glaswegian was still pursued by his native Scotland at various stages. That was primarily due to his strained relationship with Giovanni Trapattoni, who eventually settled the issue in March 2011 by capping the midfielder as a substitute against Macedonia.
Another Glaswegian of Irish descent, it was Packie Bonner who paved the way for the then Celtic teen to represent Ireland at U-16 level under Vincent Butler. McGeady's international career may have been mixed but his dedication to the cause was unflinching, even when Scotland belatedly began to take notice after Martin O'Neill handed him his Celtic debut in 2004 at 18.
An England captain at U-19 level, the Aston Villa defender left the English FA in shock by choosing to defect to Ireland in 2011. The Harrow-born centre-back said afterwards he never felt right in the English jersey, insisting his ambition to representing the country his mother Peggy and father Michael were raised in always existed.
Thanks but no thanks
Just as Rooney broke onto the scene as a 16-year-old, Mick McCarthy prompted his Ireland midfielder Lee Carsley to have a word in his Everton's team-mate's ear about declaring through his maternal grandparents. He was given short shrift by a player who went to become England skipper and record goalscorer. "It never crossed my mind," Rooney said earlier this year.
Another striker was more attainable for the FAI, yet the Tottenham Hotspur man was adamant there was no decision to make when England came calling last season. Kane's father Pat hails from Galway and recently built a house in his native land but he kept out of his son's international dilemma.
When Keane, one of the twin brothers at Manchester United, declared for Ireland at U-17 level, there was talk that he possessed the composure to become a successor to John O'Shea. However, his time at U-19 level under Paul Doolin wasn't so rosy and he opted to switch allegiance and play for England at U-21 level. It's likely the 22-year-old Burnley defender would be a full Irish international by now had he remained.
Having represented both Ireland and England at underage level, the Chelsea striker - on loan at Crystal Palace - can still ditch his homeland for Ireland. "Being English, it was always my dream to play for England, but I am not going to rule out either option," he said.
The attacker has only ever played international football for England but, like his fellow Brummie Grealish, possesses the option of changing guard through ancestry. Contact with the FAI has been established but the Norwich City player has never stated publicly his wish to switch. "He might think England is a good distance away," stated O'Neill more in hope than expectation. "But I also like to see a willingness on the player's behalf as well too."
At 18, the Arsenal playmaker has the world at his feet and is mulling over offers from England and Ireland, after sampling game-time for both. O'Neill has already spoken to the player's Waterford-born father Dave about fast-tracking the Barnsley loanee through the ranks but the decision of his pal Grealish could be a factor.
Jack Grealish is a free, extremely talented young footballer. He owes nobody but himself an explanation for his decision to put aside the green shirt of his youth for the white one of England and, maybe, the chance of taking a guaranteed place in the shop-window of next year's European Championships.