We did both of the scans with DD, and will do them again with peanut. To us, it's an important thing to do, as they can pick up if anything is wrong (especially the 20 wk one). Some abnormalities that are picked up can be fixed while still in the womb, or they can have specialists available as soon as bubs is born, and can whisk them off. ALso if anything isn't right, ir allows you to prepare mentally, and for the life change before bubs comes along. But that's just how DF and I feel, I know others are different, and it's completely up to you. You can have the 12 week scan without them doing the screening, just don't go for the blood test.