Apparently the research is from 2023:
AI Overview
A 2023 study by French National Centre for Scientific Research (CNRS) researchers and colleagues found that approximately 10% of prehistoric, Neolithic, and Bronze Age burials in Central Europe contained individuals whose gender expression did not conform to traditional male-female binaries. Analyzing over 1,200 graves, researchers identified individuals buried with items typically associated with the opposite sex, suggesting more fluid gender roles.
Key Findings on Non-Binary Burials:
Significance: While the majority of burials followed binary gender norms, a "small but significant" minority (10%) indicated non-binary identities, according to this IFLScience article.
Examples: Examples included a male skeleton in Italy buried with traditionally feminine objects like hair spirals, and a female skeleton in Germany buried with typically masculine items such as fishing gear and boar tusks.
Evidence Basis: The study, published in the Cambridge Archaeological Journal, utilized grave goods to determine gender roles, note these ResearchGate search results.
Context: The researchers noted that these individuals were not treated as marginal, suggesting they were accepted and integrated members of their communities.
Limitations: The team acknowledged that 70% of the burials lacked sufficient data for full analysis, and determining sex based solely on skeletal remains has limitations.
This study suggests that while binary, sex-matched, and gender-matched burials were dominant, they did not account for the entire, diverse, prehistoric population.