I guess we shouldn't be surprised since they've already used children in suicide bombing missions in Iraq:
Children as young as six are being used by the Taliban in increasingly desperate suicide missions, coalition forces in Afghanistan claimed yesterday.(via)
The International Security Assistance Force (ISAF), to which Britain contributes 5,000 troops in southern Afghanistan, revealed that soldiers defused an explosive vest which had been placed on a six-year-old who had been told to attack Afghan army forces in the east of the country.
The boy was spotted after appearing confused at a checkpoint. The vest was defused and no one was hurt.
"They placed explosives on a six-year-old boy and told him to walk up to the Afghan police or army and push the button," said Captain Michael Cormier, the company commander who intercepted the child, in a statement. "Fortunately, the boy did not understand and asked patrolling officers why he had this vest on."
Lieutenant Colonel David Accetta, ISAF eastern regional command spokesman, told the Guardian: "In the past we have not seen the Taliban sink that low, to use children as suicide bombers. The personnel secured the vest to make sure the child was safe."