It is the ultimate test for any parent.

Two sons playing on opposite teams in a match. Who are you rooting for?

But this is not a kickabout in the local park or a schools' match. This is a game at the World Cup.

There are four sets of siblings playing for different nations on the biggest stage of all, including Desire and Guela Doue who could face one another this summer.

Born to a French mother and an Ivorian father in the French city of Angers, the brothers play for Paris St-Germain and Strasbourg respectively.

They have taken different paths in international football, with two-time Champions League winner Desire, 21, turning out for France and overlapping full-back Guela, 23, playing for Ivory Coast.

"We tell each other everything and have no secrets," Desire told French football programme Telefoot about his relationship with his older brother.

"He's such a massive support for me in my daily life."

But could their close bond be tested in the United States?

Should France finish runners-up in Group I and Ivory Coast finish runners-up in Group E, the pair will face one another in the last-32 stage in Arlington, Texas, on 30 June.

When Ivory Coast defeated France 2-1 in a pre-World Cup friendly on 4 June, Guela sang both countries' national anthems before the match.

Desire, who had won won the Champions League with PSG five days earlier, was an unused substitute.

"It's a shame I didn't get to play against [my brother], as this was our first France-Ivory Coast match, but I'm happy, and he isn't too fed up," said Guela afterwards.

There has been only one previous case of siblings squaring off against ⁠each other at the World Cup,, external and it happened in back-to-back tournaments.

Jerome Boateng of Germany faced older half-brother Kevin Prince of Ghana in Johannesburg in 2010. Germany won 1-0. Four years later, the pair were on opposite sides again in Brazil when ⁠the group game ended 2-2.

Desire and Guela could well be next.

So, who are the other brothers appearing at this World Cup?

The Williams brothers Inaki and Nico are both Basque-born and play together for Atletico Bilbao.

But it is a different story when it comes to international football.

While Nico, 23, was player of the match when Spain beat England in the European Championship final two years ago, older brother ​Inaki, 32, turns out for Ghana.

Australia have selected Aberdeen-born centre-back Harry Souttar, 27, whose brother John, 29, is also at the World Cup with Scotland.

Their mother, Heather, is Australian, and Harry played for Scotland at youth level before switching his allegiance in 2019.

John debuted for Dundee United at the age of 16 and Scotland at 21. Harry captained Australia in their opening 2-0 win over Turkey in the group stage.

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

Sunderland striker Brobbey came on as a late substitute in the Netherlands' opening group game, a 2-2 draw with Japan.

They share the same mother but have different fathers.

In addition to the four sets of siblings playing for different countries, there are a further three lots of brothers representing their nations at this tournament.

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

And the Rotterdam-born siblings helped the Blue Sharks secure a highly impressive point as the debutants held the 2010 world champions to a shock goalless draw.

"We saw our parents cry," Laros said after the match. "The feeling is difficult to describe, it's just something you dream of."

Curacao are the smallest nation ever, by size and population, to take part in a World Cup.

For a few minutes against Germany on 14 June they dared to dream after equalising before falling away and losing 7-1.

The team included the Bacuna brothers - former Aston Villa midfielder Leandro, 34, and Juninho, 28, once of Birmingham City and Rangers.

"It's one thing that we always wished for - when we were kids we dreamed of playing together in one team on one pitch," said Juninho.

France, one of the powerhouses at this tournament, have Lucas, 30, and Theo Hernandez, 28, in their squad who play their club football for Paris St-Germain and Al Hilal respectively.

"They have this family bond," France boss Didier Deschamps said when the brothers started together for Les Bleus for the first time in 2021.

"This does not mean that it changes anything, but I will be dealing with two players who have this connection."