Who know's what the world would be like if you added 56 million (Really? 56million?!) to the population 4 generations back.
It could be very crowded, we mightn't have as much industry, another more powerful nation might have taken up the fashist cause and won.
And if that doesn't worry you, one of these 56 million might have killed, married, otherwise detoured one of your fore-bearers and prevented
the amazing You from coming into existence. I for one, wouldn't want to live in that world.
I don't think it would have so much impact on world's population, maybe we would be at 9-10 billion mark right now. In 1939 the world had 2.3 billion of people, war took 2.5% of them (Wikipedia reports up to 78m casualties), average growth since then is about 1.55%, so that's less that 2 years of "work"
If we're going to speculate, yes, it could be much worse, but there is a chance that it would be way better (I hate butterfly effect). Now to think of it, there is also great chance that if not for WW2 and cold war afterwards, we wouldn't have so many breakthroughs in technology, medicine, saving more that 56 million of people. Everything is relative I guess.