Also stated in the Abhidharma-kosha-shastra is that some children may suffer the effect of seriously negative karma that their parents accumulated. If children can suffer the consequences of their parents’ negative karma, is it not contradictory to the Buddhist teaching that one reaps what one sows and that no one can assume other’s karma? The Abhidharma-kosha-shastra explains that these children themselves already have certain negative karma. Due to the close relationship between the parents and their children, the ripening of the children’s negative karma may be expedited when the parents committed extremely evil karma.

- Quote from The Right View, "On Cause and Effect"