Is Prenatal testing beneficial for the baby at all?

The only thing that we will be having done during this pregnancy is the 20 week ultrasound to check the heart function etc. I will not behaving extensive blood testing done as we will be keeping the baby no matter what. I suppose in certain cirstances pre-natal testing would be good for the baby but in our case, there are no major areas of concern on my side of my hubby's side that would make us worry. If there was something prevalent on either side of our family that raised concern with us or the doctor then I suppose we might opt for the testing but because there are no major areas on concern, we are opting out of testing.