Shortly after England's disappointing defeat by Argentina at this summer's World Cup, boss Thomas Tuchel offered his view on why the Three Lions are struggling to win major tournaments.

"I think ball possession plays a crucial role," he said.

"It's maybe not in our DNA like it is in the Spanish DNA or Argentinian or Brazilian DNA to take the ball, control the game and the ball, which is also a big problem."

DNA (deoxyribonucleic acid), in scientific terms, usually refers to the master blueprint for life - the hereditary material in humans and almost all other organisms.

In football, the DNA of a team starts out at grassroots level, where young players are shaped and developed.

This season, the Football Association (FA) has implemented a change in youth football that could well result in a change of the DNA of the English game.

What has been introduced?

For a long time, it was considered normal for children of all ages to play 11 versus 11 matches on full-sized pitches, but in 1999 the FA introduced "mini-soccer" for under-10s.

The idea was that the small-sided variation of association football would provide youngsters with more opportunities to get a touch of the ball, and therefore be more involved than they were in large-sided games.

Up until the end of last season, the smallest variation of the game that served as an introduction to football for children under the age of seven was 5v5.

Last month, that was reduced further to 3v3.

This variation of the small-sided game does away with goalkeepers and there are also no referees - the idea is that fewer players in a "team" means those three will get more touches of the ball, and score more goals.

It is the result of two years of research by the FA in conjunction with Liverpool John Moores University, where over 400 games from under-6 to under-14 level were analysed.

"All of the research done demonstrates that those players having more touches of the ball are more engaged in the game," John Folwell, the FA's head of grassroots coach development, told BBC Sport.

"They are also making more decisions and are engaged in more physical activity, so that is the thinking behind it.

"There are no goalkeeper and no substitutes, so everyone is active in the game. They are not sitting on the side watching their mates play, or they are not standing in goal watching their friends play. They are actually involved in the game."

What do the coaches think?

With the new format having only been introduced a few weeks ago, it will take some time before teams and coaches have been able to fully adapt.

The smaller-sized format can pose logistical issues, with more games and more coaches and volunteers needed to oversee them.

BBC Breakfast recently visited Collingham FC in Nottinghamshire to see how the coaches there were adapting to the new format.

"We have three pitches going on at once and all it needs is one parent to be at work and you are trying to keep an eye on three games and nine children at once," said Michael Bland, coach of Collingham FC's under-7s.

"It is the self-officiating, dangerous tackles flying in and trying to teach the kids what a safe tackle is."

Mick Goodwin has been a youth football coach since the 1990s, so has seen it evolve from 11-a-side games to the small-sided format it is now.

"My concern is you will get one dominant player in the 3v3 where the not-so-good players will not get a touch of the ball," he said.

"What we've seen is the dominant player has been shooting from the halfway line.

"We can absolutely see the concept, I just think it needs a bit of finessing and it will be fine."

What do the parents and kids think?

The guidelines for football for children under seven is that the sport should not be about tactics or competitiveness, but about enjoyment - that is what the FA believes the new format will provide.

At Collingham FC, that was generally the consensus among those who played, and their parents.

"They are open goals and you can score more," said one child, while another added: "There's less players so it is easier to dribble around them."

One parent, Dean, said: "Before [my son] was just in goal but now he is learning to pass to other players, block stuff and be a better defender as well."

Another parent, Hannah, added: "My son has an older brother so he is used to playing in the more traditional format, so for him it has taken a bit of adapting."

Will it be bad for goalkeeper development?

One of the more criticised aspects of the new, smaller format is the lack of goalkeepers, with some concerns over how that might impact their development.

The 3v3 format only lasts for 12 months, so goalkeepers do return from under-8 level when the game progresses to 5v5.

"When you make decisions like this, there are obvious trade-offs but we don't believe it is going to be detrimental to the development of future goalkeepers," Folwell added.

"Obviously playing 3v3, players can't use their hands but they are still going to be developing skills of blocking, sliding across, needing to get between the ball and the goal.

"They will also improve their ability on the ball, which we know for goalkeepers now is an increasing technique they need to have.

"We don't believe that goalkeeping is an early specialisation position. There are lots of examples of players who have come through and ended up being goalkeepers at a later age - England goalkeeper Hannah Hampton, for example, first played outfield for a long time."

Whether the new format improves the development of English footballers will not be clear for a few years yet.

But England are far from alone in opting for 3v3 at under-7 level, with the format already part of the youth structure in Germany, the Netherlands, Norway and other countries.

Indeed, it is a format that is growing in popularity across the world.

"It is the first year of adoption and obviously these things can take time to implement and for people to accept change," Folwell said.

"What we have seen is that once people have experienced it they tend to be a convert and understand why we are doing it, because the children really love it."