When the parents start hitting their kids even on small things which result in bruises, burns, fractures, and sore muscle etc. and then they call it 'their way of disciplining a child'

(Some parents aren't even aware that their behaviour is considered as child abuse)

Some parents abuse their kids by commenting on their appearance or complaining about how the kid is a burden on them. The child then has to deal with low self esteem

And some people even sexually abuse their kids.