The British war cabinet never expected it to happen at all - from September 1939 to June 1944 and beyond they thought German fathers in uniform would eventually surrender, shots unfired, rather than see all their kiddies at home starve to death from a British sea blockade or burn to death in an Allied firebombing campaign.
America's war command also never expected to have to invade Japan's mainland - again a sea blockade and a firebombing effort would make the Japanese men in uniform surrender rather than see all their kids starve or be burned alive.
The Italians had pioneered this stuff in the Thirties, first in Ethiopia and then in Spain - bombing children in cities to get their soldier fathers to surrender out in the front lines.
The Germans had good success with burning kids to death to hasten the surrender of their soldier fathers in Warsaw, Belgrade and in Rotterdam, and with less success in London and Leningrad, despite me-too, me-too help from the Italian air forces.
The German efforts to starve British kids to death by a U-boat blockade of food shipments, until their soldier dads surrendered without a shot, almost succeeded. As did their land and air blockade of Leningrad.
Extensive combat to the death between enormous armies, to decide the fate of nations, was always a second choice Plan B in WWII
The Russians might have liked to have defeated the Germans by burning German kids to death, just as the Germans were trying to do to Russian kids with their medium bombers, but lacked the capability to produce enough reliable, big, long ranger bombers.
That mattered because they were the nation furthest from their opponent's civilian centres during most of the war.
So they were forced to put ultra huge ground forces into direct combat with equally massive German land forces for three solid years before they began to put Germans on the run.
China and Japan also lacked enough reliable big long range bombers to break the stalemate in their land war, though Japan certainly tried very hard with what medium bombers they had.
It is almost unknown, outside of their own countries, that the Chinese and Russians still suffered 350,000 to 500,000 civilian deaths from efforts by old technology medium bombers.
Those deaths match those of Germany and Japan from the prolonged, massive and very high tech heavy bomber efforts against their nations.
Is it just the cynic in me that thinks that if all the major combatant nations had gassed kids in extermination camps, almost nobody would be talking about it today ?
So we talk up the Germans' Holocaust and ignore the awkward fact that all sides attempted to starve and burn enough enemy kids to death that they might win the war without firing a shot....