The Muggle-born

There has not been any muggle-born kids for over 20 years. The only explanation is the fact that evil has been eradicated. Humans are only giving the gift of wizardry when the wizarding world is at a time of need. Well the peace is over, because the first mudblood in 20 years was just spotted at the Leaky Cauldron knowing nothing of the world she just entered into.