Unnatural sex laws are state and federal statutes — usually titled “crimes against nature,” “deviate sexual intercourse,” or “sodomy” — that criminalize sexual acts the legislature considered outside reproductive norms. After the Supreme Court’s 2003 decision in Lawrence v. Texas, these statutes can no longer be enforced against private, consensual sexual activity between adults. What remains prosecutable is conduct where consent is absent or legally impossible: sex with animals, sex with corpses, acts involving minors, and acts involving force.
What the Statutes Actually Say
State criminal codes rarely use the phrase “unnatural sex” on its own. They reach the same territory through labels like “crime against nature” or “deviate sexual intercourse,” language inherited from centuries-old statutes. The wording was kept deliberately vague because legislators considered the acts too offensive to describe plainly.
The common thread is a distinction between acts with reproductive potential and acts without. Statutory language typically covered oral and anal sexual contact, sexual acts with animals, and in some jurisdictions any sexual contact a legislature deemed contrary to public morals. Courts applying these laws focused on the specific body parts involved and the mechanics of the act, often ignoring the relationship between participants or whether both freely chose to take part.
How Lawrence v. Texas Narrowed the Reach
The 2003 Supreme Court decision in Lawrence v. Texas struck down a Texas law criminalizing same-sex sexual conduct. The Court held that “the State cannot demean their existence or control their destiny by making their private sexual conduct a crime” and that the statute “furthers no legitimate state interest which can justify its intrusion into the personal and private life of the individual.”1Justia. Lawrence v. Texas, 539 U.S. 558 (2003) The ruling placed private, consensual adult sexual conduct within the liberty protected by the Due Process Clause of the Fourteenth Amendment.
The Court explicitly limited its ruling. It did not extend to situations involving minors, people who could not freely refuse consent, public conduct, or prostitution.1Justia. Lawrence v. Texas, 539 U.S. 558 (2003) Consent became the dividing line between protected private behavior and criminal conduct.
Roughly a dozen states still have crimes-against-nature or sodomy statutes on the books. Those laws are legally dead as applied to consenting adults, but they have not been formally repealed. In at least one documented case, officers ran a sting operation arresting men under a state sodomy statute years after Lawrence; the local prosecutor declined charges because the conduct was constitutionally protected. The statutes’ continued presence on the books invites selective enforcement attempts of that kind.
Bestiality
Sexual contact with an animal is the clearest category of conduct that remains criminal under these laws, and every state now prohibits it. Several enacted their bans only within the past two decades.
Penalties vary. Roughly half of states classify a first-offense bestiality charge as a misdemeanor; the other half treat it as a felony. Many have added felony enhancements for aggravating circumstances, such as involving a minor in the act or having a prior conviction. Beyond incarceration, courts in many jurisdictions can order forfeiture of the animal, bar the offender from owning animals for a set period, and require psychological evaluation and counseling at the offender’s expense.
Bestiality remains criminal after Lawrence because the ruling’s protection extended only to autonomous adults who freely choose to participate. Animals cannot consent, and no privacy or personal-choice argument overcomes that.
Necrophilia
Sexual contact with a deceased human body is criminal across the country, though the statutory route varies. Only a handful of states name necrophilia as a distinct offense. Most prosecute the conduct under broader laws covering abuse of a corpse or mutilation of human remains.
These statutes define the prohibited conduct broadly, covering penetration, oral contact, and any touching of intimate areas of a corpse for sexual purposes. The legal reasoning parallels bestiality: a deceased person cannot consent, and the dignity interests of the dead and their surviving families provide an additional basis for criminal prohibition.
Military Rules
The Uniform Code of Military Justice handles these offenses through its own provisions. Bestiality is codified under Article 120c as “other sexual misconduct,” which prohibits a service member from engaging in a sexual act with an animal. The definition covers penetration of an animal’s mouth, anus, or genitalia by any body part or object, and oral contact with an animal’s genitalia. Because the offense is specifically codified, it is prosecuted under Article 120c rather than the General Article.
Former Article 125 of the UCMJ criminalized sodomy, including consensual acts between adults, until its repeal in 2013. In June 2024, a presidential proclamation granted full pardons to service members convicted under Article 125 for consensual, private conduct with partners age 18 and older between May 31, 1951, and December 26, 2013.2Department of Veterans Affairs. Presidential Proclamation on Certain Violations of Article 125 Under the Uniform Code of Military Justice The pardon does not erase the conviction from the service member’s record; both the conviction and the pardon appear. The proclamation excludes cases involving force, minors, bestiality, prostitution, fraternization, or abuse of a position of trust over a recruit or trainee.
Federal Reach
Most prosecutions in this area happen at the state level, but federal law reaches certain conduct through specific statutes. The most significant is 18 U.S.C. § 48, originally passed to target animal crush videos and substantially expanded in 2019. The law prohibits engaging in “animal crushing” in interstate or foreign commerce or on federal land, and also prohibits creating, distributing, or selling videos depicting such conduct. The definition of “animal crushing” covers subjecting living non-human mammals, birds, reptiles, or amphibians to serious bodily injury, and explicitly encompasses conduct that would constitute sexual assault if committed against a person. Violations carry up to seven years in federal prison.3Office of the Law Revision Counsel. 18 U.S. Code 48 – Animal Crushing
Federal law also governs sex offender registration through the Sex Offender Registration and Notification Act (SORNA), which creates a three-tier system based on offense severity. Tier I offenders register for 15 years, Tier II for 25 years, and Tier III for life. Tier I registrants with a clean record for 10 years can reduce their registration period by five years; Tier II offenders receive no such reduction. Registrants who plan to travel internationally must notify registry officials at least 21 days before departure. That notification is forwarded to the U.S. Marshals Service and then to INTERPOL, which alerts law enforcement at the destination.4Office of Sex Offender Sentencing, Monitoring, Apprehending, Registering, and Tracking. SORNA: Information Required for Notice of International Travel
Penalties and What Follows a Conviction
Sentences range widely depending on the specific offense, the jurisdiction, and any aggravating factors. Bestiality can carry anything from months in county jail for a misdemeanor to several years in state prison for a felony. Conduct involving minors triggers dramatically harsher sentences, often with mandatory minimums. Fines run from a few thousand dollars for basic offenses to tens of thousands when a child victim is involved.
What follows the sentence is often more disruptive than the sentence itself. Sex offender registration is the most significant collateral consequence. Under SORNA, registration periods of 15 years to life are standard depending on tier classification. Registry information appears in public databases, and many states impose residency restrictions that bar registrants from living within set distances of schools, parks, or childcare facilities.
Employment consequences are severe. Background checks reveal the nature of the conviction, and many states bar registered sex offenders from working in fields involving contact with children, vulnerable adults, or the public in certain capacities. Professional licensing boards in healthcare, education, and law routinely deny or revoke credentials. The stigma on a background check closes most other doors as well. These consequences last years or decades after the sentence is served, and the path to expungement for a felony sex offense is narrow in most jurisdictions. Filing fees alone often run between $120 and $215 before attorney costs.