Interesting, though I also don't put much stock in the idea that the parent's birth weight plays much role in baby's birth weight. Too many other factors influence baby's birth weight IMO.
I was 9lbs7oz at birth, spent a week in the NICU for post-maturity, almost dying from all the complications.
DH was 6lbs6oz at birth, born to a mother who was told by her doc to gain absolutely no more than 15 pounds during pg.
We have four children.
Twins, 38w3d, with birth weights of 6lbs12oz and 6lbs8oz. Pre-eclampsia with symptoms beginning at 36w2d. Total weight gain of 17 pounds (225 at delivery).
Singleton, 38w0d, 8lbs10oz. No pre-e. Total weight gain of 34 pounds (230 at delivery).
Singleton, 37w1d, 7lbs8oz. Pre-e with symptoms beginning at 34w5d. Delivered 15 pounds less than pre-pg weight (250 at delivery).
I just have big babies if you ask me. My twin pg was the longest pg of the three, and they were good sizes for twins at that gestation. My two singletons were also big for the gestational age they were born at. I started all three pg very much overweight, the third by far being the worst, thus the overall weight loss. But my babies were all still pretty big at birth.
If I went to 42 weeks, I'd have 10 pounders easy I think. Of course, my blood pressure would never cooperate long enough for me to even get close to that point most likely.