Conceivable Privacy Rationale Sustains “No-X” Birth-Certificate Policy Under Rational Basis Review

Introduction

In de la Fuente Díaz v. Gonzalez Colon (1st Cir. Sept. 1, 2026), six nonbinary persons born in Puerto Rico (the “Plaintiffs”) challenged Puerto Rico’s birth-certificate gender-marker format, which—via the Application for Gender Change—allowed only “Female” or “Male,” not an “X” marker. They sued Puerto Rico officials in their official capacities (the “Puerto Rico” defendants), seeking declaratory and injunctive relief under 42 U.S.C. § 1983.

The core issue on appeal was whether Puerto Rico’s refusal to add an “X” marker (the “Birth Certificate Policy”) violated the Equal Protection Clause. The district court granted summary judgment to Plaintiffs, holding the policy failed even rational basis review and inferring the distinction was “born of animosity.” The First Circuit vacated and remanded.

Summary of the Opinion

The First Circuit (Montecalvo, J.) reviewed the summary judgment ruling de novo, assumed without deciding that rational basis review applied, and held that Puerto Rico’s “no-X” policy survives rational basis review. The court emphasized that rational basis review allows upholding a classification if any “reasonably conceivable” facts could support it, even if that rationale was not the one relied on by the district court.

The court identified a rational basis grounded in Puerto Rico’s legitimate interest in protecting privacy rights: Puerto Rico permitted binary transgender changes in response to Arroyo González v. Rossello Nevares, which found the prior regime violated privacy by forcing disclosure of transgender status. By contrast, Plaintiffs conceded that an “X” marker “inherently discloses” nonbinary status and thus did not press a parallel informational privacy theory. On that record, the court concluded it was “conceivably rational” for Puerto Rico to treat the two groups differently.

Analysis

Precedents Cited

  • Arroyo González v. Rossello Nevares, 305 F. Supp. 3d 327 (D.P.R. 2018)
    • Role in this opinion: The First Circuit treated Arroyo González as the legal and practical catalyst for Puerto Rico’s existing binary-change mechanism. In Arroyo González, the district court required Puerto Rico to issue a new birth certificate reflecting an applicant’s “true gender” without disclosing transgender status, grounding that remedy in constitutional privacy concerns. That history supplied the First Circuit’s key “conceivable” rationale: the Commonwealth’s binary marker changes were privacy-remedial, while an “X” marker could be viewed as privacy-diminishing (or at least not privacy-protecting) because it signals nonbinary status.
    • Doctrinal move: The court used Arroyo González not to extend privacy protection to nonbinary markers, but to justify differential treatment under equal protection at the rational basis stage.
  • United States v. Skrmetti, 605 U.S. 495 (2025)
    • Role in this opinion: The controlling template for rational basis review. The court quoted Skrmetti for: (1) the “wide latitude” afforded to legislatures; (2) the “any reasonably conceivable state of facts” standard; and (3) the principle that where “plausible reasons” exist, judicial inquiry ends.
    • Practical effect: Skrmetti enabled the First Circuit to uphold the policy based on a rationale not limited to the two interests the district court identified.
  • City of Cleburne v. Cleburne Living Ctr., 473 U.S. 432 (1985)
    • Role in this opinion: Provided the baseline formulation: classifications are presumed valid if rationally related to legitimate interests. It also reinforced deference under rational basis review, as later synthesized in Skrmetti.
  • Romer v. Evans, 517 U.S. 620 (1996)
    • Role in this opinion: The district court relied on Romer to infer that the classification was “born of animosity.” The First Circuit, while quoting Romer through Skrmetti, effectively rejected the district court’s animus inference by identifying a rational, non-animosity-based justification (privacy-related legislative line-drawing).
  • FCC v. Beach Commc'ns, Inc., 508 U.S. 307 (1993); Mass. Bd. of Ret. v. Murgia, 427 U.S. 307 (1976) (per curiam); R.R. Ret. Bd. v. Fritz, 449 U.S. 166 (1980); Dandridge v. Williams, 397 U.S. 471 (1970); Lindsley v. Nat. Carbonic Gas Co., 220 U.S. 61 (1911)
    • Role in this opinion: These cases supply the canonical rational basis principles quoted in Skrmetti and applied here: line-drawing is “peculiarly a legislative task,” classifications need not be mathematically precise, and courts uphold if any conceivable facts support the distinction.
  • McKenna v. Me. Dep't of Health & Hum. Servs., 152 F.4th 14 (1st Cir. 2025); Jeneski v. City of Worcester, 476 F.3d 14 (1st Cir. 2007)
    • Role in this opinion: The First Circuit invoked these to emphasize the objective nature of rational basis review: the question is not actual motives, but whether “anyone, including the judge,” can conceive of a rational reason.
  • Doherty v. Merck & Co., 892 F.3d 493 (1st Cir. 2018); Eulitt ex rel. Eulitt v. Me. Dep't of Educ., 386 F.3d 344 (1st Cir. 2004)
    • Role in this opinion: Framed Plaintiffs’ burden at rational basis: they must negate any “fairly conceivable” rational link between the classification and legitimate goals.
  • A.C. by Waithe v. McKee, 23 F.4th 37 (1st Cir. 2022); Donahue v. City of Boston, 371 F.3d 7 (1st Cir. 2004)
    • Role in this opinion: Provided the First Circuit’s description of rational basis as “forgiving.”
  • Wadsworth v. Nguyen, 129 F.4th 38 (1st Cir. 2025); Anvar v. Dwyer, 82 F.4th 1 (1st Cir. 2023); Barnes v. Fleet Nat'l Bank, N.A., 370 F.3d 164 (1st Cir. 2004)
    • Role in this opinion: These cases governed the summary judgment posture and the standard of review: de novo review and viewing evidence in the light most favorable to the nonmovant on each motion.
  • Cornwell Ent., Inc. v. Anchin, Block & Ankin, LLP, 830 F.3d 18 (1st Cir. 2016)
    • Role in this opinion: Used to hold that Plaintiffs waived any developed argument that the Birth Certificate Policy violated their privacy rights in a manner comparable to Arroyo González.

Legal Reasoning

  1. Assumption of rational basis, not selection of scrutiny.

    Like the district court, the panel assumed without deciding that rational basis review applied, avoiding the contested question whether classifications involving transgender/nonbinary status trigger heightened scrutiny.

  2. Rational basis is not confined to the government’s litigating positions.

    The panel emphasized that rational basis review permits upholding a law if any conceivable rationale supports it, regardless of whether Puerto Rico’s briefing below (or the district court’s accounting) captured that rationale. This is a direct application of the Beach Communications/Skrmetti conception of “reasonably conceivable” supporting facts.

  3. The privacy-based distinction is “conceivably rational.”

    Puerto Rico’s existing allowance for binary transgender changes was tied to Arroyo González and its concern with forced disclosure of transgender status. For nonbinary persons, Plaintiffs conceded that an “X” marker “inherently discloses” nonbinary status and did not pursue a parallel privacy theory. The panel then treated Puerto Rico’s interest in protecting privacy rights as a legitimate state interest, and found a rational relationship between that interest and a policy that (a) permits binary changes that can reduce unwanted disclosure, while (b) declining an “X” marker that would itself signal a stigmatized or sensitive status.

  4. Rejection of the district court’s animus inference.

    The district court inferred animus because it could not “conceive of any rational basis.” The First Circuit’s identification of a plausible, privacy-linked rationale removed the predicate for that inference under Romer as the district court applied it.

Impact

  • Harder path for “X marker” claims under rational basis alone.

    The decision signals that, where courts apply rational basis review, “X marker” challenges may fail if the government can point (or a court can conceive) to any legitimate interest—here, privacy—supporting incremental or partial recognition.

  • Strategic shift toward alternative theories.

    Because the panel’s rationale turned on Plaintiffs’ waiver and concession regarding privacy, future plaintiffs may more squarely litigate Due Process/privacy theories, compelled speech/First Amendment theories, or argue for heightened scrutiny, rather than rely on rational basis.

  • Clarifies the “conceivable rationale” methodology in the First Circuit post-Skrmetti.

    The opinion reinforces that rational basis review is exceptionally deferential: courts may uphold based on rationales not advanced by the government, and line-drawing need not be comprehensive.

  • Procedural consequence: vacatur and remand.

    The district court’s injunction requiring Puerto Rico to add an “X” option was undone; the case returns for further proceedings consistent with the panel’s equal protection holding (while leaving other constitutional claims unaddressed on appeal).

Complex Concepts Simplified

Rational basis review
The most deferential equal protection test. A policy is upheld if it is reasonably related to any legitimate government interest. The government does not need the best reasons—or even the actual reasons—so long as a plausible reason can be conceived.
“Any reasonably conceivable state of facts”
A court may hypothesize facts or rationales that could justify the classification; the policy survives if such a rationale is plausible. This makes invalidation difficult unless the challenger can negate all plausible justifications.
Informational privacy (as discussed in the opinion)
A constitutional interest (as framed in Arroyo González) in avoiding compelled disclosure of sensitive identity information. Here, the panel reasoned that an “X” marker could itself reveal nonbinary status, undermining a privacy-based argument on this record.
Waiver on appeal
If a party does not adequately develop an argument, the court may treat it as waived and decide the case as though the argument were not made. The panel relied on waiver principles to note Plaintiffs did not preserve a developed privacy-rights theory comparable to Arroyo González.
Animus inference
A conclusion that a law is motivated by hostility rather than legitimate purposes. Under rational basis review, the existence of any plausible legitimate rationale generally prevents an animus-based invalidation.

Conclusion

de la Fuente Díaz v. Gonzalez Colon establishes (at least for cases reviewed under rational basis) that a jurisdiction may survive an equal protection challenge to an “X” gender-marker refusal where a court can conceive a legitimate rationale—here, a privacy-protective explanation tied to the remedial history of Arroyo González v. Rossello Nevares and Plaintiffs’ concession that an “X” marker inherently discloses nonbinary status. The First Circuit’s vacatur and remand underscores a broader lesson: post-United States v. Skrmetti, rational basis review is highly forgiving, and challengers must negate not only the government’s stated reasons but any plausible justification a court may conceive.