A mother's obese status has only a small effect on a child's obesity, according to a new study in PLoS Medicine (2008;5:doi:10.1371).
Debbie Lawlor, PhD, and others worked with data from a 1991-1992 longitutional study, with 9-year and 11-year follow-ups, involving 4,091 sets of parents. They were looking to see if the developmental over-nutrition hypothesis was true -- that is, if women who are overweight or obese during pregnancy make the child more likely to be overweight or obese themselves.
The data proved otherwise. Testing for the A variant of the FTO gene, which has been linked to maternal obesity, they found no connection between a pregnant mother's and a child's obesity.
Increased body-mass index of both parents, however, was linked to the child's increased body-mass index. The mother's weight was slightly more correlational than the father's, however.