I think bad eating habits are true of many people. I know my sister's kids used to eat more junk food than any kid should, but she (and her kids) are thin. That they're thin seems to then 'excuse' my sister for her poor choices on their behalf, and shields her from the kind of scrutiny overweight parents seem to be under.

So I maintain that fat parents do not necessarily equate to fat kids. Yes there are some overweight families. There are also families with thin parents and overweight kids. And there are overweight parents with thin kids. I think it's far to specific to assume that being fat makes you the kind of person who will not make good choices for your family. I think any parent is capable of that.