Embodiments of a method and/or system for characterizing a microorganism-related condition (e.g., human behavior condition, disease-related condition, etc.) for a user can include one or more of: generating a microbiome dataset for each of an aggregate set of biological samples associated with a population of subjects, based on sample processing of the biological samples; processing a supplementary dataset associated with one or more microorganism-related conditions for the set of users; and performing a microorganism-related characterization (e.g., human behavior characterization, disease-related characterization, etc.) process for the one or more microorganism-related conditions, based on the supplementary dataset and/or microbiome features extracted from the microbiome dataset.