There's more recent examples but a bit of digging produced this
On January 21 1998 a Labrador Retriever killed a two year old child called Megan Stack. Early in the morning, her father heard her scream and ran downstairs to find the dog biting her head. The dog, "Toby", was 80 pounds, eight...
I'm very much in the camp of bad owners create bad dogs, have kept working terriers all my life - none of whom have ever bit a human or attacked another dog outside their kennel companions - but I would never trust any of my dogs with very young children whether they were mine or someone else's...