Plaintiffs Elizabeth Mirabelli, Lori Ann West, and others brought this action on behalf of themselves and a putative class challenging school district policies regarding the social transition of students who identify as transgender. The central dispute concerns whether California’s public school teachers and staff may notify parents when a student uses a different name or different pronouns or gender expressions that diverge from the name and sex assigned to the child at birth.
Defendants designated two expert witnesses: (1) Christine Brady, Ph.D., a clinical psychologist; and (2) Darlene Tando, LCSW, a licensed clinical social worker.
Plaintiffs contended these experts’ opinions: (1) relied on unreliable principles, including quasi-spiritual beliefs; (2) lacked sufficient factual basis; (3) contradicted constitutional principles; (4) contained internal inconsistencies; and (5) were cumulative.
Psychology Expert Witness
Christine Erin Lam Brady is a clinical psychologist and Clinical Associate Professor at Stanford University School of Medicine’s Pediatric and Adolescent Gender Clinic.
She holds a Ph.D in Child Clinical Psychology, an M.A. in Psychological Sciences, and a B.S. in Psychology.
Social Work Expert Witness
Darlene A. Tando is a licensed clinical social worker who has counseled gender nonconforming youth since 2006.
Tando holds a Masters degree in Social Work, with a concentration in
children, youth and families, and a Bachelor of Arts in Psychology.
Discussion by the Court
A. Challenges Go to Weight, Not Admissibility
Plaintiffs argued that Tando’s statements that gender identity is “part of a person’s soul” and her references to “male and female brains” reflected quasi-spiritual rather than scientific foundations for her opinions.
While such statements can affect the credibility of the witness, they did not render the entirety of the testimony inadmissible. Plaintiffs also noted the absence of studies examining social transition without parental involvement, while the cited literature presumes parental participation. The Court acknowledged the absence of supporting research for healthy gender transition without parental involvement. This absence, however, did not render inadmissible Tando’s testimony based on broader clinical experience with transgender youth. The limitation concerned the weight rather than admissibility.
Plaintiffs argued that the experts’ opinions run contrary to constitutional principles that sometimes require individualized determinations of parental fitness. At the same time, there is also a general constitutional presumption that fit parents act in their children’s best interests.
While these principles, including the presumption that fit parents act in their children’s best interests, maintain their vitality, expert opinion admissibility under Rule 702 does not turn on constitutional alignment; such issues go to the merits.
B. Expert Disagreement Is Not a Basis for Exclusion
In essence, Plaintiffs contended that their experts are “right” and Defendants’ experts are “wrong” requiring exclusion. “Correctness,” however, is not the admissibility standard.
Here, Defendants’ experts need only demonstrate their opinions meet Rule 702‘s requirements by a preponderance of the evidence, not that they have definitively proven causation or eliminated all alternative explanations. As a result, the Court found that such disagreement about whether there are mental health benefits from transitioning concerned weight, not admissibility.
Additionally, because this matter proceeds to a bench trial, standards for excluding expert testimony apply with additional flexibility.
Alternatively, Plaintiffs requested limiting Defendants to one expert witness (either Brady or Tando). Brady and Tando represented distinct disciplines. For example, Tando’s counseling emphasized social systems, skill development, and client advocacy.
Defendants argued that the two experts offered different disciplinary approaches, and each obtained different perspectives from different client bases. The Court found these differences sufficient.
Held
The Court denied the Plaintiffs’ motion to exclude the testimony of Defendants’ experts Darlene Tando and Christine Brady.
Key Takeaway:
Plaintiffs highlighted the fact that both experts — in their own practices — refused to treat minors without parental consent. The reality of their own practices did tend to contradict their view that schools may facilitate gender transition safely without parental involvement. Even so, the experts’ ongoing clinical experiences counseling transgender youth provided a sufficient foundation here for admissibility.
Case Details:
| Case Caption: | Mirabelli V. Olson |
| Docket Number: | 3:23cv768 |
| Court Name: | United States District Court, California Southern |
| Order Date: | October 23, 2025 |
