There are many causes of developmental delay, the third generation of IVF can only exclude people with high genetic risk diseases, if the parents have genetic diseases that cause developmental delay, they can be excluded through PGD technology during the third generation of IVF, but there is no guarantee that the fetus will not be born with developmental delay. If fetal developmental delay is caused by the mother’s environment, emotions, drugs, radiation and other factors, it cannot be ruled out by the third generation IVF technology, and there is also a certain genetic mutation in the process of gestation that may lead to fetal developmental delay, and the third generation IVF can only rule out the fetal developmental delay due to high genetic diseases. Diseases that can be avoided by third generation IVF include autosomal genetic diseases, such as thalassemia and sickle cell anemia; dominant inheritance, such as myotonic dystrophy, and X-chromosome structural and numerical variations. In the case of developmental delay, it is important to seek medical advice and treatment as prescribed by the doctor.