Abandoned DNA & the Ownership of Sperm

You leave your DNA on every cup you drink from. A doctor once turned a patient's spleen cells into a patented product without telling him. A woman allegedly kept a man's semen after oral sex, conceived a child, and won child support. Who owns the biological material we shed, sell, and leave behind — and what does "own" even mean when the thing in question is you?

In this TalksOnLaw interview, Joel Cohen sits down with Glenn Cohen of Harvard Law School, faculty director of the Petrie-Flom Center and one of the world's leading scholars of bioethics and law, to explore the strange frontier where property law meets the human body — from abandoned DNA and patented cells to the Craigslist sperm donor, the right to know one's biological father, and the frozen embryos fought over in divorce.

Mr. Moore's Spleen

Professor Cohen opens with Moore v. Regents, the leukemia patient whose physician recognized the commercial value of his cells, kept drawing samples after treatment ended, and built a cell line worth millions. The California Supreme Court gave Moore a claim for lack of informed consent — a doctor must disclose a commercial motive — but refused to recognize conversion, fearing liability would chill biotechnology. Cohen uses the case to ask the deeper question: what would ground a property right in one's cells? Not Lockean labor, since no one works to have valuable genes. Perhaps personhood — the intuition that stops a stranger from copying your face at a plastic surgeon. He extends the puzzle through Henrietta Lacks, whose cells underpinned decades of research while her family received nothing, and the Havasupai tribe, whose blood samples were used for studies they never agreed to, and notes that today's biorepository consent forms routinely strip donors of commercial rights "belt and suspenders."

The Saliva on the Cup

Turning to privacy, Cohen explains that the law gives almost no protection to discarded genetic material: police may test the saliva on an abandoned cup — he recounts the investigators who mailed a suspect a fake class-action mailer and tested the licked envelope — and the Fourth Amendment's garbage cases have been extended to shed DNA. The protections that exist come afterward, in the Genetic Information Nondiscrimination Act's limits on insurers and employers. But Cohen pushes back on "genetic exceptionalism": your browsing history and phone location may reveal more about your mental health than your genome, and the answer is to protect both kinds of data, not to treat DNA as a sacred diary. He touches on 23andMe's sharing of customer data with Pfizer, the Gattaca date, and the hard cases of duties to disclose heritable conditions to spouses and children.

Sperm, Twins, and the Trobriand Islanders

The conversation then moves to sperm, which the law treats differently in part because family law attaches to it. Cohen offers an anthropological detour — a culture that does not connect sperm to fatherhood, and identical twins who transplanted a testicle so the infertile brother could father a child with genetically identical sperm — to show how much of our sense of ownership is psychological rather than biological. Then the case that opened his Harvard job talk: Phillips v. Irons, in which a man alleged his partner retained his semen after oral sex and inseminated herself. The court dismissed his conversion claim — he had abandoned the material — allowed a claim for emotional distress to proceed, and, in the paternity action, made him pay child support regardless.

Sperm From Skin

Cohen then turns to in vitro gametogenesis: the prospect, already achieved in animals, of turning adult skin cells into sperm or eggs. If the saliva on the cup could one day produce a child, is that like sperm theft or too many steps removed? And if any cell can become an embryo, what happens to arguments about the moral status of embryos? The technology, he says, is within the foreseeable future, and the law has not begun to think about it.

The Craigslist Donor

From abandoned material the conversation moves to reproduction on purpose, beginning with the Kansas case of William Marotta, who answered a lesbian couple's Craigslist ad, signed an agreement disclaiming parenthood, and was pursued for child support by the state when the family later sought public assistance. A court held him the legal father: the right to support belongs to the child, and parents cannot contract it away. Cohen explains the patchwork — states with Uniform Parentage Act provisions that cut off donor liability when insemination is done through a physician, states without, and the courts' discomfort with donors who attend birthday parties and start to look like fathers. His practical advice to known donors is blunt: use a doctor, and keep your distance. Joel presses the libertarian case for enforcing agreements; Cohen answers with the hypothetical that unsettles courts — why enforce a contract about artificial insemination but not one signed before intercourse?

Shift Work and Gift Narratives

Drawing on the sociologist Rene Almeling's Sex Cells, Cohen describes how sperm banking is framed as employment — celibacy windows, motility testing, payment only for samples that pass, ninety-five percent of applicants screened out — while egg donation is framed as a gift. He tours the catalogs, the "sold out" donors, the failed Nobel sperm bank, the estimate that three to eight percent of people are wrong about who their father is, and Denmark's improbable role as the world's sperm exporter.

The Right to Know

Most of Europe requires that donor-conceived children be able to learn their donor's identity at eighteen; the United States, with the partial exception of Washington State's opt-out statute and open-identity banks, does not. Cohen explains what that right actually is — a name, not a relationship — and the empirical trade-off: donor numbers fall when anonymity ends, though the pool can shift toward older men, and his own studies suggest known donation would require paying roughly a third more, with a quarter of current donors unwilling at any price. He describes the Donor Sibling Registry's amateur detectives, the accidental-incest concern behind proposed caps on offspring, and the one American case, Johnson v. Superior Court, in which a court compelled a donor to testify under a protective order.

Sperm After Death, Embryos After Divorce

The final segment covers posthumous reproduction — sperm retrieved from the dead, Social Security benefits for children conceived after a father's death, trusts that name "descendants" — and the frozen-embryo cases in which nine or ten state supreme courts have refused to let one former spouse implant embryos over the other's objection, recognizing a right not to become a genetic parent that overrides signed disposition agreements. Cohen flags a 2016 amicus brief from the Thomas More Law Center arguing that state law protecting fetal life should tip such disputes toward implantation, and offers his own view: a right not to procreate should exist, but he does not find it in the Constitution, and the Supreme Court has never said a word about reproductive technology.

What to Know Now

The hypotheticals in this conversation have become case law and headlines. The abandoned-DNA question moved from the cup to the cloud: in 2018 investigators identified the Golden State Killer by uploading crime-scene DNA to a public genealogy database and tracing his relatives, a technique since used to close thousands of cases; Maryland and Montana enacted the first laws regulating forensic genetic genealogy in 2021, and the Department of Justice issued an interim policy in 2019. Consumer genomics delivered the privacy lesson Cohen anticipated: 23andMe suffered a breach exposing nearly seven million users' data in 2023 and filed for bankruptcy in 2025; its genetic database was sold that July to TTAM Research Institute, a nonprofit led by its co-founder, for $305 million — prompting state attorneys general to remind customers of their deletion rights under the roughly twenty state privacy laws now in force. In Carpenter v. United States (2018), the Supreme Court declined to extend the third-party doctrine to cell-site location data, the first constitutional recognition that the "leaking data" Cohen compares to shed DNA can retain Fourth Amendment protection. The Henrietta Lacks story reached a resolution in 2023, when her family settled its suit against Thermo Fisher Scientific over the commercialization of HeLa cells. Moore and Phillips v. Irons remain the law. And in vitro gametogenesis has advanced: researchers have produced live mice from two genetic fathers, and in 2025 a team at Oregon Health & Science University made human eggs from skin-cell DNA, though none yielded viable embryos; human IVG remains in the laboratory, while Cohen and others have begun mapping the legal questions he raises here.

On the reproduction side, the law has moved on nearly every front. The Marotta case reversed: in November 2016 a Kansas judge ruled that Marotta was not the child's legal father, because the women had intended to be the parents, though the physician-insemination gap he fell into persists in many states. The 2017 revision of the Uniform Parentage Act, since adopted in several states, provides that a donor is not a parent regardless of whether a physician was involved, and adds a European-style provision giving donor-conceived people access to identifying information at eighteen unless the donor has opted out. Colorado went further: its Donor-Conceived Persons Protection Act (2022), the first of its kind in the United States, ends anonymous sperm and egg donation for donations made after January 1, 2025, guarantees identity disclosure at eighteen, and caps each donor at twenty-five families — resolving, for one state, the trade-off Cohen quantified; his study of current donors, since published, found that about 29 percent would stop donating if anonymity ended. In 2025, the discovery that a single Danish donor carrying a cancer-linked gene variant had fathered at least 197 children across Europe renewed calls for Europe-wide limits on offspring per donor. "Fertility fraud" statutes in more than a dozen states now criminalize physicians who secretly use their own sperm, a wave triggered by consumer DNA tests. On posthumous conception, Astrue v. Capato (2012) held that Social Security eligibility turns on state intestacy law, leaving the state-by-state pattern he describes intact. The Missouri dispute behind the Thomas More brief, McQueen v. Gadberry, ended in 2016 with the appeals court treating the embryos as marital property that neither spouse could use without the other's consent. Elsewhere the frozen-embryo debate took the turn the amicus brief foreshadowed: Arizona enacted a statute in 2018 awarding disputed embryos to the spouse who wishes to use them, and in LePage v. Center for Reproductive Medicine (2024) the Alabama Supreme Court held that frozen embryos are "children" under the state's wrongful-death statute, halting IVF in the state until the legislature enacted immunity for providers. Dobbs v. Jackson Women's Health Organization (2022) removed the constitutional floor beneath reproductive decisions and, as Cohen anticipated, left reproductive technology to the states. Cohen, now Deputy Dean at Harvard, remains the leading scholar of these questions.