Table of Contents Introduction I. An Overview of forensic DNA Testing II. The Science of Genetic Appearance estimation A. Developing Tools B. Assessing (In)accuracy 1. Insufficient Data 2. Low-Quality Samples 3. Genetic Admixture C. Current Tools D. Estimating Phenotypic Traits for Casework 1. Biogeographic Ancestry 2. Facial Morphology 3. Skin Pigmentation 4. Hair Pigmentation and Texture 5. Eye Pigmentation 6. Body Height 7. Age E. Looking to the Future III. Scientific and ethical Concerns A. Risks Discrimination, Stigma, and Racial Profiling B. Reveals Sensitive Genetic, Lifestyle, and Health Information C. Risks Wrongful Arrests and Convictions D. Lack of Transparency or Oversight E. Costly to the Public Without Clear and Corresponding Benefits IV. LEGALITY A. In the United States, Regulation Gaps and Deficiencies B. International Regulations Offer Lessons C. Constitutionality V. Avenues for Legislative Reform A. Moratoria and Prohibitions B. Limitations on Permissible Uses C. Judicial Oversight D. Communication of Results E. Public Disclosure F. Procurement and Funding Conditions G. External Oversight Bodies H. Enhanced Protection of Genetic Data in Non-Forensic Databases Conclusion Appendix
INTRODUCTION
In October 2022, the Edmonton Police Service of Canada (the "Service") published a computer-generated portrait of an alleged suspect in an assault case to its social media. (1) Unable to identify leads in the case, the Service had hired a private company to analyze DNA from the crime scene in order to estimate the physical characteristics of the person of interest, a practice known as "forensic DNA phenotyping." The image the Service published portrayed a Black man; statistics accompanying the portrait described the person of interest as being of East African ancestry, having dark brown or brown skin, and having either brown or black eye color.
Soon after publication, public outcry at the Service's distribution of and reliance upon this computer-generated "generic image" led the Service to remove the image from social media and apologize. (2) A spokesperson for the Service wrote, "The potential that a visual profile can provide far too broad a characterization from within a racialized community and in this case, Edmonton's Black community, was not something I adequately considered." (3) The Service's statement underscores a simple but perhaps stunning fact: in the purchase and application of a controversial technology to analyze a person's most intimate information, the Edmonton Police Service had been the sole decisionmaker.
This result is not an anomaly. Five years earlier, the New York City Police Department (NYPD) had hired the same company to use forensic DNA phenotyping to estimate the appearance of a person of interest in a murder case. This company represented to the NYPD that the person of interest was of African ancestry, (4) which led the NYPD to collect, compare, and store DNA from over 360 Black and Latinx community members. (5) This practice, in which law enforcement request a large number of people to share their genetic samples in order to identify a person of interest, has been described as a DNA dragnet. (6) The New York State Department of Health, which oversees private DNA laboratories operating in the State, had not approved the operation of the forensic DNA phenotyping company in New York State at the time. (7) Like the Service, the NYPD lacked legislative guidance, so they relied upon their own judgment about whether and how to apply this tool. (8)
Appearance estimation tools are one category among a panoply of genetic techniques and DNA collection practices that have transformed criminal investigations. (9) After investigators collect DNA from a crime scene, they typically compare the DNA to a database that contains the DNA profiles of, in part, previously convicted individuals. When there is no match between the crime scene DNA and the database, investigators may turn to other genetic techniques to try to solve the crime. Like forensic DNA phenotyping, these methods sometimes lack legislative authorization and may not require judicial approval to employ. (10)
To investigate persons of interest whose DNA profiles are not contained in an existing government database, law enforcement have collected DNA from a multitude of unusual sources (11): a nine-year-old child's genetic screening data from when he was a newborn, to investigate the child's father; (12) a victim's DNA from a rape kit, to identify and arrest the victim in an unrelated burglary; (13) tissue from a daughter's Pap smear (a procedure to collect and test cells for cervical cancer), to investigate the child's father; (14) and surreptitiously gathered items such as a child's McDonald's soda, (15) licked envelopes, (16) and face masks, (17) to investigate the persons who used the objects. While these measures can produce extraordinary benefits, sometimes solving crimes decades after they occurred, they also come with societal risks, such as privacy intrusions and wrongful identifications.
Some developers of the genetic tools available to law enforcement have received critique for reliance on genetic data from inappropriate sources. For illustration, forensic researchers have relied on genetic data from: research participants, stored in databases intended for health research such as UK Biobank; (18) the Uyghur population in China, collected pursuant to an alleged health check; (19) public ancestry websites; (20) convicted and arrested community members' DNA in the United States and abroad; (21) and DNA databases that may contain genetic profiles obtained without informed consent. (22)
Unlike in the early years of forensic DNA testing in the United States, when national and state legislation accompanied the expanding use of genetic testing in the legal system, federal legislative architecture has yet to emerge to guide or curb these myriad genetic practices. While there has been robust reporting and discussion amongst scholars about the ethics of these practices, (23) nearly all of these techniques and tools remain available to law enforcement and forensic researchers in the United States. These practices are not always disclosed in affidavits or in discovery, so their use may not be visible to defendants, judges, or juries. (24)
This Article advocates for deliberative bodies at the federal, state, and local levels to regulate investigative genetic techniques--and examines genetic appearance estimation as an illustrative example. Also described as "molecular photofitting," forensic DNA phenotyping technologies purport to predict externally visible characteristics (eye color, hair color, skin color, hair texture, and face shape) from DNA. (25) Put another way, these tools predict or estimate an individual's looks (one's "phenotype") solely from one's genetic information (called one's "genotype"). (26)
Appearance prediction tools include forensic DNA phenotyping, biogeographic ancestry estimation, and age estimation. Forensic researchers are working to expand these predictive categories further to include behavioral characteristics like smoking habits. Researchers in the field often refer to biogeographic ancestry and age estimation as distinct from forensic DNA phenotyping because age and ancestry are not necessarily apparent from one's physical appearance. For the reader's ease, this Article uses the terms forensic DNA phenotyping and genetic appearance estimation as inclusive of biogeographic ancestry and age estimation.
Like many law enforcement investigative techniques in the United States, forensic DNA phenotyping lacks statutory authorization in most states even while it has been used in most states. (27) Like the research of other forensic tools, studies in the field have sometimes relied upon genetic data from controversial sources. In certain countries, legislative bodies have chosen to regulate forensic DNA phenotyping, (28) offering lessons for the United States.
Forensic DNA phenotyping goes to the heart of key legal questions, which this Article discusses, regarding the use of genetics in the criminal legal system and whether the nature of the genetic analysis matters for the Fourth Amendment. These questions include whether there are limits to government analysis of DNA when it reveals complex and sometimes intimate genetic traits; (29) and whether, if law enforcement does not need a warrant to collect discarded items, (30) it ever requires judicial approval to test involuntarily shed DNA.
The science of phenotyping and the legal landscape of forensic DNA testing have meaningfully evolved since the publication of other legal analyses of the technology's use in the United States. (31) This Article builds upon and benefits from prior discussions of the technology. It is based on reviews of the relevant scientific and legal literatures, conversations with stakeholders, as well as original freedom of information requests. This Article has a U.S. focus, but provides international context when instructive.
Part I introduces readers to forensic DNA testing. Part II contrasts traditional forensic DNA testing with genetic appearance estimation. Because stakeholders' views with respect to forensic DNA phenotyping vary, Part III identifies the scientific and ethical concerns associated with forensic DNA phenotyping. Part IV considers the legality of these tools internationally and domestically. Although other countries have passed laws to regulate the use of genetic appearance estimation tools, the United States has no federal law that governs the technology. Emblemizing the limited oversight of police investigatory practices nationally, forensic DNA phenotyping is in use even in the few states that appear to prohibit the technology. This Part discusses how forensic DNA phenotyping relates to constitutional issues that scholars have debated in the wake of the Supreme Court's...
