I'm not convinced that anyone can predict the size of the pup at all. We have two little guys. Their mom weighed 5 lbs and their dad weighed 3 lbs. The breeder thought they would weigh somewhere in the range of 3-5 lbs. When we took them home at 12 weeks old, one of them weighed 2.5 lbs and the other weighed 1.5 lbs. Now, fully grown, they both weigh 6.5 lbs. So, the double the weight at 12 weeks rule didn't work, and predicting their weights based on what their parents weigh didn't work, either!
I'm sure by the time your little one is fully grown, you won't really care. We're so in love with our boys that I don't care if they weigh 5 lbs or 50 lbs - they're part of the family now.
