Get a biopsy, NOT just an endoscopy! Some GI's do just the endo, but ends can often miss damage, and that is not enough for an official diagnosis to get qualified for studies or trials. Not to say that the biopsy can't miss damage too, but its more likely to confirm it. If its positive for damage, you and your son will always know for sure that all the trouble (and it is a significant burden) is for a really good reason, and there will be no going back if it gets too difficult or if he eats gluten and has no symptoms. Symptomless gluten ingestion in celiacs is common starting after childhood, but damage is still being done. I would not wait for a biopsy, as reducing gluten consumption will throw off the results and you said your house is going gluten free. If the biopsy results come back negative, I would eliminate gluten anyway and assume the blood tests are correct and not discount them. It could be that the celiac has not been active long enough to do measurable damage to the intestines. I would not think you would get a false positive on the blood tests, but false negatives seem commonplace. If even one blood test was positive, along with the strong family history, I would take the docs offer to diagnose positive for celiac.