When I was born, my parents owned two GSDs, who they were advised to get rid of - by the midwives - because "they'll kill the baby!". My parents chose to ignore their advice, and luckily... those two dogs became my protectors, even to the point of getting between me and my parents trying to smack me. Never growled, never bit anyone in the family, thought I was theirs to all extents and purposes. But the male was a trained guard dog, who often used to chase would-be burglars out of various Army properties. The female was considered "nasty" because my mother - who had spent her entire adolescence working with GSDs in the show rings, and grown up with other dogs - thought it funny to teach her to "see off" soldiers on the estate we lived in. She loathed men in uniform, to the point where if my soldier father came home in his - she wouldn't let him past the front door until my mother (and then, later, me) told her to. When I was 10 and she was 11, she fought to keep a burglar out of our home and was so badly beaten by the bastard, that she died from internal bleeding shortly after.
When I was 12, my father brought home the stables he worked at's "ratter" - a 9 month old GSD who had been badly abused. And trained to kill rats. My best friend; walked sedately by my side, without need of a lead, no matter where we were, never showed any signs of aggressive behaviour, stress, or dominance at any point in the next 11 years - and when my daughter was born, with special medical needs, he became "her" dog/protector. Other than a fight with his own 2 year old pup (my mother's GSD-cross), due to the pup charging at the door when someone knocked at 11pm-ish, then turning to run back along the hallway, but colliding with my dog, who was probably having an adrenaline surge and suddenly found a barking dog full on in his face - so reacted, he was the epitome of the perfect dog.
He was still never left alone with my daughter, however, whilst my parents are very fortunate that the midwives suggestion didn't become reality.
When my son was 18 months old, we got a spaniel. Softest of all my dogs. The most submissive, too. The most he ever did to my son was to sit on him, to keep him in place, if someone knocked on the door. Never left alone with him, or my older daughter. I have a Kokoni now - who has Border Collie and Corgi in her, with potential indicators of a terrier of some sort, and maybe Spaniel. She is my assistance dog, who is - out of all the many dogs I've shared my life with over the last 46 years - the best trained of the lot. And she loves babies/small children, to the point where if she hears one crying, then she wants to know why. But she will never be left alone with any potential grandchildren (my two are adults now), because she can be a bit possessive, gets a little over-enthusiastic about bringing parcels into the house, and my parents current (hulking) GSD is absolutely terrified of her. Don't know why, but I figure there is a reason. She is also a rescue, with dodgy origins, who is neurotic and displays terror in certain situations. Not a dog I would ever trust with a baby/toddler.
All of my dogs have been trained, but also treated with kindness and respect for the fact that they're not little humans in fur coats... they are animals, with very powerful jaws, who if they took it into their heads to hurt someone, or kill a child who is annoying them - each and every one of them, from the softy Spaniel to the "ratter" GSD, from the assisting Kokoni to the trained guard GSD duo, has the potential to actually do so. I really wish more people who bring a dog into their home, would grasp this concept. Train and socialise their puppies with other dogs and situations, understand their body language - even if just a basic grasp - and respect that they don't all want to be climbed over by shrieking, curious fingered little ones. Ensure their dog knows who is "boss" (ie, that it's not the dog!) and have a lot of boundaries in place, along with teaching the dog that "no" is all it needs to hear, to stop what it's doing - not a giggly "no, Fluffikins, oh please don't... stop Fluffikins, that's not very nice, oh you are a naughty dog, aren't you, Fluffikins?", because that just confuses and perhaps even ramps up the dog's misbehaviour.
My thought is that we need to bring back the Dog Licenses and have a course before being able to get one, with a "pass" and "fail" set in place. We do with driving, after all. Both a car and a dog can cause life-altering injuries and/or death, at the end of the day.