Don't be angry. As first time parents, you and your wife need to be more active in asking questions. It's normal for the doctor to count the wrong due date. The method of counting is usually based on the last period and a normal M period of 28 days. If your wife is period is more than 28 days, there would be a certain delay. Of course, a good and detailed doctor will be able to adjust the due date but it can only be confirmed with the help of ultrasound. That's why Dr. Sin queried about your wife's due date. I can understand that Dr. Sin may not be able to do the screening test for your wife if the baby is too young because of higher risk of miscarriage and inaccurate information generation. Keep yourself and your wife relaxed and think about that you are going to have a baby soon. Tell your wife to take it easy, it is not a big deal, be a happy mom-to-be, then your baby can be a happy baby too.