Genetic epidemiology and the future of disease prevention and public health.

"As he chats with the young mother, the doctor flicks a cotton swab into the mouth of her infant son, collecting a small sample of mucus from inside his cheek. In the back room of his office, he inserts the sample into a machine, which extracts DNA from the mucus cells and compares it with the genetic material on a dime-size chip. Minutes later, a computer printer begins to spit out a list of the infant's genes. Fortunately, all but a few genes are labeled 'normal.' It is those few that the doctor discusses as he explains the results to the mother. 'Your son's genetic inheritance is generally good', he says 'but he is somewhat predisposed to skin lesions. So starting right away, he should be protected against excessive exposure to the sun.' And the doctor warns, 'he may well be susceptible to cardiovascular disease later in life. To lessen this risk, after about age 2, he should begin a lifelong low-fat high fiber diet'" (1, p. 24).