Carl Sagan

Scientists can routinely predict a solar eclipse, to the minute, a millennium in advance. You can go to the witch doctor to lift the spell that causes your pernicious anaemia, or you can take Vitamin B12. If you want to save your child from polio, you can pray or you can inoculate. If you're interested in the sex of your unborn child, you can consult plumb-bob danglers all you want… but they'll be right, on average, only one time in two. If you want real accuracy… try amniocentesis and sonograms. Try science.