Are Different Populations Fairly Represented in Single-Cell Omic Atlases?

Single-cell Omic (sc-Omic) atlases are transforming biology and medicine, yet their demographic representativeness has not been systematically evaluated. We conducted a secondary analysis of >13,500 samples from the Human Cell Atlas (HCA), Human Tumor Atlas Network (HTAN), and PsychAD Consortium, using metadata curated in GREI and supplementary data linked to publications. Benchmarking against global and US general and disease-prevalence data, we found a striking, pervasive European overrepresentation and underrepresentation of Asian and Latino individuals. Nearly 70% of HCA samples lacked ancestry annotation, HTAN tumors were 78% European, and PsychAD showed more balanced African representation but markedly few Asians. Sex distributions in these atlases also skewed compared to published disease prevalences. These disparities highlight that current sc-Omics resources risk embedding inequities into AI foundational models, biomarker discovery, and therapeutic development.