'Generational curse' is a false doctrine that came up comparatively recently. Neither Jesus nor the apostles taught about it. 'Visiting the iniquity' in Ex.20:5 does not mean that God will punish children for the father's sins, because that is something God has expressly said is unlike Him (De.24:16;Ez.18:10). But it implies that the natural consequences of the sins of parents will be borne by the children for generations. Many can identify how parental abuse or neglect, especially in the childhood, has affected them lifelong. Too much strictness or discipline, and unrealistic expectations have driven many to have poor self-image and a belief that whatever they do is not going to be enough. Favouritism and comparison with siblings have compelled some to be always proving themselves before others in order to feel important. On the other hand, neglect by the parents (under the guise of giving the children freedom to develop their own personalities or avoiding 'control') may result in self-centred children growing up with hardly any social skills, or others getting into bad company and learning all the wrong things.
When God tell us to train our children in the right way (Pr.22:6), it is because they need a lot of training. They have a great potential, and it is not automatically that they learn to follow God and fulfil His special plan for them. All the world is teamed up against God and it attacks godly values and practices through distorted forms of 'human rights', 'respect for all', 'secularism', and 'political correctness'. It stirs up the children through the media with desire for pleasure and feeds them with violent and immoral forms of pleasure. The children grow up with scant respect for authority, expecting that it is their right to get what they want and learning to use illegitimate means to fool others and to have their own way.
Parents themselves are so caught up in the rat race for career growth, more luxury, more comfort, more fun, etc., that they have no time either to sort out their marital problems or to attend to the children. The dysfunction which they have inherited from their parents is passed on to their children in an amplified way. Some people think this is all a curse or witchcraft and try to break it through special prayers and rituals!
But it is very simple for us to see what is going on if only we think about it. The solution is not to send the children for counselling(!), but for the parents to recognise what they have done wrong and change their ways! What we do as parents affect not only our children but also generations to come. We should be the ones to stop the dysfunction now, and to make every effort to set things right. It may mean apologising to our children(!), and showing our repentance now with spending time with them, listening to what they have to say, trying to understand their points of view, and relating to them in a respectful way. God wants to do that (Mal.4:6).