Families, or rather parents are in a state of¯ux: sometimes they row a lot, they divorce, they go and live together again and they die. This is why more and more children grow up in family forms other than the nuclear families with their biological fathers and mothers. What, in the long run, is the effect of this on the well-being of adolescents and young adults between 12±30? We have examined intact families that function well, mediocre or badly, one-parent families and stepfamilies after a divorce and one-parent families after being widowed. The data derive from the Dutch longitudinal panel study``Utrecht Study of Adolescent Development'' (USAD). The results of 1772 respondents between 12 and 30 years old are presented from the third wave by the end of 1997. Compared to youngsters of well functioning nuclear families, the youngsters of discordant nuclear families show a worse physical and mental health, their parental ®xation is not so strong, they tend to drink more alcohol, smoke more cigarettes and use more soft drugs. Children of divorced families are notable for their relational behaviour: they enter into relations at an early age, usually they are more sexually experienced and they report more relational problems. Children of widowed one-parent families do well. In other family types girls suffer a little more from the burden of life than boys. It appears that the effects are hardly different when the children leave home. #