In scripture, what does "generational curse" refer to? Let's look at Exodus 20:5b-6, "for I the Lord your God, am a jealous God, punishing the children for the sin of the fathers to the third and fourth generation of those who hate me, but showing love to a thousand generations of those who love me and keep my commandments."
Regarding this text, John Calvin states in Harmony of the Law, Vol. 2, "Exposition of the 2nd Commandment," that when "God declares that he will cast back the iniquity of the fathers into the bosom of the children, he does not mean that he will take vengeance on poor wretches who have never deserved anything of the sort; but that He is at liberty to punish the crimes of the fathers upon their children and descendants, with the proviso that they too may be justly punished, as being imitators of their fathers."
Likewise, Jeremiah 32:18 states, "You show love to thousands but bring the punishment for the fathers' sins into the laps of their children after them." The Hebrew meaning here has to do with children who continue in the sinful patterns of their fathers. The idea is that there is "personal" accountability to behave differently.
This integrates beautifully with the idea in the behavioral sciences about patterns of dysfunctional behavior in our family of origins being continuous. What people are exposed to in their childhoods can very easily be carried into their adult lives — and their new nuclear families.
Children of alcoholics can easily replicate patterns. Domestic violence and childhood abuse is often repeated. Undiagnosed or untreated mental illness can lead to dysfunctional and damaging patterns in our adult lives.