The higher the mother's blood sugar, the more risk for the newborns, the study found. Researchers took into account obesity, age and family history of diabetes and still found the mother's blood sugar independently affected the infant's size and health.
Well, duh. It's the relative condition of the mother at the time of pregnancy. Her family isn't linked in any way shape or form. The woman's family history adds a preponderance to the possibility the woman will likely contract diabetes at some point, but
at the time of pregnancy is the sole issue - if she does not have diabetes or high blood sugar during pregnancy, there is no relevant issue.
They could also poll 1000 people to find a popular answer to something. That only remains valid for 1000 people. Compared to finding out how all 300 million Americans feel, a poll asking 1000 Americans is grossly underwhelming and as such inaccurate. Therefore, the study making this claim is suspect also.