Campaigners and religious groups have jointly called for the British army to stop recruiting people under the age of 18 in an open letter to the Ministry of Defence.
All the bishops from the Church in Wales are among a number of co-signatories from the campaign group Child Soldiers International calling for the current recruitment age of 16 to be raised.
The letter, addressed to defence minister Mark Francois said the MoD does not deploy soldiers until the age of 18.
The MoD argues recruitment can be beneficial for young people, who can apply from the age of 15 and seven months, providing there is parental consent.
“It provides them challenging and constructive education, training and employment, equipping them with valuable and transferable skills for life,” a spokesman told the BBC.
Other signatories include the Rev Sally Foster-Fulton, convenor of the Church and Society Council of the Church of Scotland, and peace groups run by Christians including Baptists, Methodists, Roman Catholics and Quakers.
The letter said: “Current recruitment policy channels the youngest most disadvantaged recruits into the most dangerous frontline combat roles.
“Those recruited at 16 have faced double the risk of fatality of adult recruits throughout the conflict in Afghanistan.”
“We commend the MoD for having ceased routinely deploying children into conflict, but challenge its failure to stop recruiting them.”
Child Soldiers International said its own analysis of MoD figures showed that last year 880 16-year-olds enlisted in the Army, 40 per cent fewer than the year before - 1,470 - and just a quarter of the 3,600 enlisted a decade earlier.
The fall has been matched by rising drop-out rates, the group claimed.
It added that of all the 16-year-olds recruited by the Army last year, figures recently released showed that nearly half, or 410, left during training.
Richard Clarke, director of Child Soldiers International, highlighted the minimum recruitment and conscription age for joining the army during the first world war as 18, with deployment at 19.
He said: “It's time for the MoD to recognise what more and more young people and their parents are realising - that enlisting at 16 is not in their best interests."