It presents the ultimate challenge for any parent.

Two sons lining up on opposing sides in a contest. Which team receives their support?

Yet this scenario goes far beyond a casual game in the neighborhood or a school fixture. It unfolds during a World Cup encounter.

Four pairs of siblings represent separate countries on football's grandest stage, among them Desire and Guela Doue who may meet this summer.

The duo, born in the French city of Angers to a French mother and Ivorian father, feature for Paris St-Germain and Strasbourg in that order.

They have pursued separate routes in international football, as two-time Champions League winner Desire, 21, represents France while overlapping full-back Guela, 23, appears for Ivory Coast.

"We share every detail and keep nothing hidden," Desire explained to French football show Telefoot regarding his bond with his older sibling.

"He provides enormous encouragement in my everyday routine."

Nevertheless, might their strong connection face a trial in the United States?

If France ends second in Group I and Ivory Coast finishes second in Group E, the brothers could clash in the round of 32 in Arlington, Texas, on 30 June.

After Ivory Coast beat France 2-1 in a pre-World Cup friendly on 4 June, Guela performed both nations' anthems ahead of kickoff.

Desire, who had secured the Champions League with PSG five days previously, remained an unused substitute.

"It is unfortunate I missed the chance to play versus my brother, since this marked our first France-Ivory Coast fixture, yet I feel pleased while he shows little frustration," Guela remarked later.

Only one earlier instance exists of siblings opposing each other at the World Cup, and it occurred across consecutive editions.

Jerome Boateng of Germany confronted older half-brother Kevin Prince of Ghana in Johannesburg during 2010. Germany prevailed 1-0. Four years afterward, the pair again stood on different sides in Brazil as the group match concluded 2-2.

Desire and Guela may follow that example next.

So, which other brothers appear at this World Cup?

The Williams brothers Inaki and Nico both originate from the Basque region and play club football together at Atletico Bilbao.

International duty tells a separate story, however.

While Nico, 23, earned player of the match honors as Spain defeated England in the European Championship final two years earlier, older brother Inaki, 32, competes for Ghana.

Australia named Aberdeen-born centre-back Harry Souttar, 27, whose brother John, 29, also attends the World Cup with Scotland.

Their mother, Heather, holds Australian nationality, and Harry represented Scotland at youth level prior to changing allegiance in 2019.

John made his Dundee United debut at age 16 and his Scotland debut at 21. Harry led Australia in their opening 2-0 victory over Turkey during the group phase.

Meanwhile, Ghana's Dutch-born defender Derrick Luckassen, 30, joins his half-brother Brian Brobbey, 24, at the event.

Sunderland striker Brobbey entered as a late substitute in the Netherlands' opening group fixture, a 2-2 draw against Japan.

They share the same mother yet have different fathers.

Besides the four pairs of siblings playing for separate countries, three additional sets of brothers represent their nations at this tournament.

Laros Duarte, 29, started for Cape Verde against Spain on 17 June and was substituted by his younger brother Deroy, 26, in the 61st minute in Atlanta.

The Rotterdam-born pair helped the Blue Sharks claim an impressive point as the newcomers held the 2010 world champions to a surprising goalless draw.

"We watched our parents shed tears," Laros noted after the match. "The emotion proves hard to put into words; it remains something one imagines."

Curacao stands as the smallest nation ever, measured by area and population, to appear in a World Cup.

For several minutes against Germany on 14 June they allowed themselves hope after leveling the score before fading and losing 7-1.

The squad featured the Bacuna brothers - former Aston Villa midfielder Leandro, 34, and Juninho, 28, previously with Birmingham City and Rangers.

"It represents something we always hoped for - as children we imagined playing together in one team on one pitch," Juninho stated.

France, among the leading sides at this tournament, include Lucas, 30, and Theo Hernandez, 28, in their squad; they play club football for Paris St-Germain and Al Hilal respectively.

"They share this family connection," France manager Didier Deschamps remarked when the brothers started together for Les Bleus for the first time in 2021.

"This does not alter the situation, yet I will manage two players who possess this link."