"As to how they know, you can figure that out.  Blood typing, Rh factor, hair and eye color, all those genetic things - you probably know more about them than I do.  Anyhow it is a mathematical certainty that Mary Jane Lyle Smith was his mother and Captain Michael Brant was his father.  All the factors are matters of record for the entire crew of the Envoy; there probably never were eight people more thoroughly measured and typed.  Also it gives Valentine Michael Smith a wonderfully fine heredity; his father had an I.Q. of 163, his mother 170, and both were tops in their fields.