Ms. C, a 32-year-old woman with no history of mental disorder, visits her family physician exhibiting mild symptoms of depression. She has been listless and riddled with guilt since her long-time boyfriend moved out the previous month, along with their golden retriever. They had been having money problems since her shifts at work had been cut back, and she missed her boyfriend and their dog. She had been having trouble sleeping and had spent her sleepless nights scouring the Internet for hints about her state of mind and how to “snap out of it.” Ms. C tells her physician that she read a website about the serotonin transporter gene, 5-HTT or something, and that mutant versions of this gene make people more susceptible to depression. She asks for the physician to administer a test for this genetic mutation and warns that if he won't order it she will just find another doctor who will.

Mr. and Mrs. D have recently moved to the area. They have an 11-year-old son, E, who has been acting like “a child they don't even know anymore” since making friends with older kids in the new neighborhood. He won't listen to them around the house, refuses to clean his room, always breaks his curfew, acts up in class, and sometimes smells like cigarette smoke. The same thing happened with Mrs. D's brother at that age, and he wound up in a juvenile facility by age 14. She and her husband are concerned that maybe this kind of behavior runs in the family, and so they make an appointment with an internist to run a battery of genetic tests on E.