The cocker population is HUGE so there are more of them out there ending up in homes that don't handle them properly - hence you hear stories about aggression. They are busy little dogs, workers generally more so than show cockers but both types are pretty energetic and bright so need mental stimulation and exercise... a bored, underexercised cocker can be naughty - like any dog can.
I've had 2 cockers from pup around babies and young children and even the one who was 'Puppy from hell' has grown into a very sweet natured tolerant little chap - I trust him with my 1yr old daughter and he's great fun with my over the top 7 yr old son. The first cocker I had was even sweeter and more gentle - even as a pup. He was a serious livewire but SO gentle with children, I once had to untangle 5x 2 yr olds from him whist he was cornered against a wall and he never batted an eyelid, he know I'd always rescue him so just waited patiently
Most of the time however
, I'm very careful to teach the children to respect the dogs, treat them kindly and give them their space when eating etc so I've never had a problem - I don't give the dogs high value treats (bones for example) when the kids are around either as that's just asking for trouble with any dog.
If you've had other dogs around your kids, you'll be fine just applying a bit of common sense with a cocker. Make sure you buy a well bred health tested pup from a reputable breeder also
I know of both show types and working type cockers in family homes with young children and I've never heard of a problem - they both love the chaos and busy days of family life and love being included in EVERYTHING
Is there a reason you've decided on a worker rather than show type?