The Mormon church announced plans to pull as many as 185,000 youngsters from the Boy Scouts on Thursday as it looks to start its own scout programme.
The Church of Jesus Christ of the Latter Day Saints is the biggest sponsor of the Scouts in the US and has had close ties for more than a century.
The Church insisted the decision was not related to the Scouts' decision to allow gay troop leaders in 2015 but because it wanted a new programme more tailored to specific Mormon teaching, according to Associated Press.
It is part of a more widescale exodus of The Boy Scouts to other, more fringe, ideological youth organisations after the century old movement became embroiled in a row over gay leaders.
Organisations such as the Southern Baptist Convention's Royal Ambassadors and the Seventh Day Adventist's Church's Pathfinders programme are similiar to the Boy Scouts and although saying they 'don't want to gain off of someone else's misfortune' are seeing the opportunity to gain members.
The Boy Scouts put the loss at 130,000 boys but the Church said it was 185,000 13-18 year olds that will be taken out the movement.
Around 280,000 younger Mormon boys aged 8-13 will remain in the programme, the Church said.
It comes after years of the Church trying to develop a scouting programme to roll out around the world, including for its nearly 16 million members outside the US.
In a statement, the Church said that the Scouts' programmes for teenagers aged 14 to 18 have historically been difficult to implement within the religion, and that the new programme will be tailored to foster Mormon teenagers' 'spiritual, social, physical and intellectual' development.
Despite saying they were 'deeply troubled' by the Boy Scouts' decision to allow gay adult leaders, the Mormon Church stuck with the organisation after being assured they could keep appointing their own leaders according to their conservative religious beliefs.
But their decision now to take older boys out is a worrying sign for the centuries old movement that has a steady year-on-year decline in membership.
