Vertical transmission of overweight: evidence from a sample of English adoptees

Vertical influences can significantly shape children overweight by affecting both genetics and the environment children are exposed to. This paper examines the vertical (parental) transmission of child overweight drawing upon a fifteen year sample of English adults and their children, both adopted and biological, for which we can retrieve clinical measures height and weight. We find that, when both parents are overweight, children exhibit an increased likelihood of overweight, irrespective of whether they are adopted or biological children. When both parents are obese as opposed to overweight the picture is different. We find that the likelihood of child overweight increases by 16.7 percentage points among natural (non-adopted) children but only by 4.5 percentage points among adopted children. This suggests that the transmission of overweight when both parents are obese is not merely genetic, and what has been called vertical or parental transmission plays a non-negligible role. Our findings are validated by are a battery of robustness checks.