This study contributes to the understanding of how social mortality patterns are reproduced across generations by documenting associations of women's marital status at childbirth in the beginning of last century with selected health indicators across three subsequent generations of their offspring, and by highlighting a special set of plausible mechanisms linked to this particular event in history. We use the Multigenerational Uppsala Birth Cohort Study (UBCoS) database consisting of 12,168 individuals born at Uppsala University Hospital in 1915-1929 (UG1), their children (UG2) and grandchildren (UG3). Results showed that men and women born outside wedlock (BOW) in early twentieth century Sweden were at an increased risk of adult mortality compared to those who were born in wedlock (BIW), and the men were also significantly less likely to reach their 80th birthday. The question of childhood social disadvantage and its long-term consequences for health is then taken one step further by examining their offspring in two subsequent generations in terms of four specific anthropometric and psychological outcomes at the time of military conscription, all known to predict disease and mortality later in life. Results showed that sons of men BOW as well as sons and grandsons of women BOW had significantly lower psychological functioning and cognitive ability. Regarding body mass index and height, however, significant associations were found only among descendants of men BOW. The anthropometric and psychological disadvantages found among descendents of individuals BOW were partly mediated by their social class background. The four outcomes observed early in the lives of UG2s and UG3s do in fact constitute early health determinants, each potentially influencing longevity and mortality risk in these generations. We conclude that the social disadvantage imposed on those BOW in early twentieth century Sweden appears to be reproduced as a health disadvantage in their children and grandchildren, with likely consequences for mortality among these.