30% of the population will have one or two of those genes (DQ2 and DQ8) but only about 1% of the population has celiac disease. Having the genes just meas that you have a greater chance of developing celiac disease compared to the rest of the population. You can have celiac disease without those genes. I know of at least one board member who has celiac disease but not the genes. The genes are found in about 95% of celiacs though.
My rambling is basically to say that even without the genes, the kids could have a chance of developing celiac disease. Without knowing the genetics, first degree relatives od celiacs have about a 10% chance of developing celiac disease. If your kids do continue to eat gluten, they should be retested every couple of years as celiac disease can develop, or finally reveal it's presence, at any time of of life. If your kids have symptoms, and test negative, you may want to make them gluten-free for 6 months to see if they improve. It could be non-celiac gluten intolerance (NCGI), or it could be celiac disease - those tests aren't perfect.
My three kids were tested and were all negative but two of them had some symptoms (nothing severe). I made the family gluten-free (gluten is not nutritionally required - it's a food of convenience now a days) and their health improved. Just something to consider.