“Our DNA is Our Blueprint”

The brief for Alonzo Jay King, in the arrestee DNA sampling case, Maryland v. King, correctly maintains that “The collection of an individual’s DNA raises profound privacy concerns.” Respondent’s Brief, at 45. It then elaborates that

Our DNA is our blueprint: an individual’s DNA contains not only deeply personal information about the subject’s medical history and genetic conditions, but also information that can be used to make predictions about a host of physical and behavioral characteristics, ranging from the subject’s age, ethnicity, and intelligence to the subject’s propensity for violence and addiction. See, e.g., Center for Genetics Education, The Human Genetic Code–The Human Genome Project and Beyond (2007), tinyurl.com/cgegenome; Mark A. Rothstein & Meghan K. Talbott, The Expanding Use of DNA in Law Enforcement: What Role for Privacy?, 34 J.L. Med. & Ethics 153, 158 (2006).

Id. at 45-46. Regardless of how the Supreme Court decides the case, the Court would be ill-advised to uncritically repeat these assertions about (1) “our blueprint” and (2) “age, ethnicity, … intelligence, … violence and addiction.”

I. “Our Blueprint”

Does the human genome tell us as much about an adult human being as the blueprint of a building tells about the building? In the preface to a recent book cited in the brief, Harvard University population geneticist Richard Lewontin argues that the metaphor of “blueprints” is oversimplified if not misguided: “we expect genes ‘for’ not only skin color and eye shape but also intelligence, disease, and musical ability. [But] it is an error to suppose that the DNA sequence of an organism predicts its total nature and life history.” Another contributing author writes that “the genes most of us envision inside us, calling the shots and determining our characteristics, are myths.” A blueprint determines the height of a building, but genes (not yet known with any exactitude) give a range of response for the height of human being.

II. Predicting Age, Ethnicity, Intelligence, Violence, and Addiction

Yes, DNA sequences can “be used to make predictions about … age, ethnicity, and intelligence [and] violence and addiction.” So can a Ouija board or a horoscope. The two authorities cited in the brief do not maintain that such predictions are any good. The Australian report, Center for Genetics Education, The Human Genetic Code–The Human Genome Project and Beyond (2007), cautions that determination of the entire DNA sequence contained in the human genome will not enable geneticists to look at a person’s DNA sequence and predict everything about their appearance, behaviour and other characteristics.” Id. at 6. It does not even mention inferences about age, ethnicity, intelligence, violence, or addiction.

The other publication, by Rothstein and Talbott, does mention some of these characteristics, but only as the subjects of possible–and possibly specious–“claims.” These commentators wrote that “[i]t is likely that within a short period of time there will be claims of the ability to make behavioral genetic predictions about such matters as sexual orientation, intelligence, addictive behavior, musical ability, and temperament.” Mark A. Rothstein & Meghan K. Talbott, The Expanding Use of DNA in Law Enforcement: What Role for Privacy?, 34 J.L. Med. & Ethics 153, 158 (2006). It now is seven years since they made this prediction. Have any new claims been made? More to the point, have they been confirmed? Claims are cheap. Proof is hard.

Beliefs also are cheap, in the sense of being easy to acquire. Once acquired, they can be difficult to dislodge. A Supreme Court opinion that reinforces the popular dogma of genetic determinism would be irresponsible–and unnecessary. In upholding as constitutional the compulsory sterilization of “a feeble minded white woman,” the Supreme Court infamously wrote that “[t]hree generations of idiots are enough.” Buck v. Bell, 274 U.S. 200, 207 (1927). One such opinion was enough. The genome is not a medical history. No one can tell from my DNA what diseases I have had, how much I weigh, or how high my blood pressure is. Identical twins rarely die of the same disease. They have a less than 50/50 chance of having the same common diseases.

This is not to deny that the genome contains substantial information. Some of it is highly predictive or diagnostic of some conditions, like sickle-cell anemia. That alone is sufficient to raise “profound privacy concerns.”


  • Jordana T. Bell & Tim D. Spector, A Twin Approach to Unraveling Epigenetics, 27 Trends in Genetics 116 (2011) 
  • Genetic Explanations: Sense and Nonsense (Sheldon Krimsky & Jeremy Gruber, eds. 2012)

Cross-posted to Forensic Science, Statistics, and the Law.