Story highlights Teams at the forthcoming World Cup are taking differing approaches to the issue of sex

U.S. head coach Jurgen Klinsmann is relaxed on the matter, with players able to see their wives

His Mexican counterpart Miguel Herrera has called on his players to exercise restraint

Bosnia's Safet Susic says: "There will be no sex in Brazil"

The Mexicans will be abstaining, one German is more open-minded while the Bosnians will only have themselves for company.

It's a debate as old as time -- should football stars keep it clean between the sheets to maximise athletic performance?

U.S. national team coach Jurgen Klinsmann is taking a relaxed view on in-competition coitus during the 2014 World Cup.

"I think we are very casual in the way we approach things," Klinsmann, a World Cup winner in 1990 with Germany, told Fusion TV.

"Their families can come pretty much any time. They will be at the games, they can come by at the hotel, we will have barbecues together.

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"Every nation is different. I've played in different countries where, you know, you didn't see your girlfriend or your wife for two months. ... Every team and every country handles that differently, based on their culture.

"So I respect the Mexican approach because it's more their culture at that moment. I think we have a group of guys together and an environment together that is very open, very casual.

"But once we go on the field for training and also for the games, we are very serious and down to business."

As Klinsmann suggested, the Mexicans will be adopting a more chaste approach, with "El Tri" coach Miguel Herrera warning his players to restrain from sexual activity during the month-long tournament.

"If a player can't go one month or 20 days without having sexual relations, then they are not prepared to be a professional player," Herrera told Mexican newspaper Reforma.

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"All the players we have selected have a pretty good resume, they all have won great things, they have been champions, and they know what we want to achieve.

"So then we will not be looking for sex or having sex at the World Cup just to have it, we are going to go after what we came for, a competition that gives us the opportunity to rise above and do something really great. ... We talked about it because there was a buzz."

Music to the ears of Bosnia-Herzegovina's coach Safet Susic, who according to British newspaper the Daily Star, told his players "there will be no sex in Brazil."

Yet Susic, who is leading Bosnia at its first major tournament, has allowed one small concession.

"They can find another solution, they can even masturbate if they want. I am not interested what the other coaches do, this is not a holiday trip, we are there to play football at the World Cup."

Do you think footballers should be allowed to have sex at the World Cup? Let us know in the comments below