Unless someone really knows their lines, I think the only way to get a dog the size you want is to buy an older one. My two Sassy(7lbs) and Sydney(4lbs.) have produced puppies from just 3lbs to 12 lbs. in the same litter. It happens all the time, I get upset when I see people promising that the puppy you buy from them will only get to a certain size, I was promised my dog would only get to be around 6lbs. and today she weighs 13. It is disappointing to expect a smaller dog and of course you love your dog, but were hoping it to stay smaller, but glad to hear you love your dog regardless of him turning out bigger than expected.