## Facts

- Rhonda Hendrix sued on behalf of her infant son, G.P., alleging product liability and negligence arising from the use of an Evenflo Discovery Model 212 child restraint system (CRS).
- Hendrix and G.P. were involved in a low-speed collision (about 10–12 mph) when G.P. was fifteen days old.
- Hendrix alleged G.P. was properly restrained in the rear center seat and that the carrier was “false-latched” into its base, dislodged during the collision, and caused head trauma.
- Evenflo disputed the account and contended the CRS was in the front passenger seat and that the injury resulted from interaction with the passenger airbag during deployment.
- G.P. suffered a head injury; later he was diagnosed with syringomyelia and autism spectrum disorder (ASD).
- Hendrix claimed the collision-related head trauma caused G.P.’s ASD and other conditions, relying on expert medical causation testimony using differential etiology.

## Issues

1. Whether the district court abused its discretion under Federal Rule of Evidence 702 and Daubert by excluding plaintiff’s expert testimony that the collision and head trauma caused G.P.’s ASD.
2. Whether, after exclusion of ASD-causation testimony, partial summary judgment was proper on ASD-related compensatory damages due to lack of admissible causation evidence.

## Decision

- The Eleventh Circuit affirmed the exclusion of the ASD-causation expert opinions.
- The court held the district court acted within its gatekeeping discretion because the experts’ differential etiology was not shown to be reliably applied to ASD causation on these facts.
- The court affirmed partial summary judgment for Evenflo on ASD-related compensatory damages because, without admissible expert evidence on causation, a reasonable jury could not find the accident caused G.P.’s ASD.
- The court reaffirmed that federal evidentiary standards govern admissibility in diversity cases, while state law governs substantive causation.

## Legal Principles

- Under Rule 702 and Daubert, expert testimony must be relevant and reliably grounded in sound methodology; courts evaluate principles and application, not conclusions alone.
- Differential etiology can be acceptable, but it is not self-validating; the expert must (i) identify plausible causes supported by medical science and (ii) reasonably rule out alternative causes with a reasoned explanation.
- Temporal sequence alone (symptoms appearing after an event) is insufficient to establish medical causation for admissibility purposes.
- In diversity cases, state substantive law does not relax the federal admissibility standard for expert testimony; Rule 702 and Daubert control in federal court.
- When a claim requires expert medical causation proof and the plaintiff lacks admissible expert evidence, summary judgment is appropriate.

## Conclusion

The Eleventh Circuit upheld the district court’s Daubert exclusion of expert opinions attributing a child’s ASD to a minor collision and head trauma because the experts did not reliably support general and specific causation through scientific literature and adequate consideration of alternative causes; without admissible causation evidence, ASD-related damages could not go to a jury.


Hendrix ex rel. G.P. v. Evenflo Co., 609 F.3d 1183 (11th Cir. 2010)