Analysis of 1,772 Hispanic adults aged 50+ revealed striking sex differences in how gut bacteria relate to mobility impairment. Women with movement difficulties showed reduced microbial diversity and 84 unique bacterial species alterations, while men showed none. Both sexes shared 15 species changes, including increased Streptococcus and Lactobacillus alongside depleted Eubacterium bacteria. This sex disparity in gut-mobility connections represents a significant finding that could reshape how we understand aging-related physical decline. The bacterial alterations appear linked to metabolic pathways involving hormone metabolism and inflammatory compounds like imidazole propionate. While observational data cannot prove causation, these patterns suggest women's gut ecosystems may be more vulnerable to mobility-related disruption, or conversely, that targeting female-specific microbiome patterns could offer therapeutic opportunities. The research fills a critical gap since women experience mobility loss at higher rates than men, yet most microbiome-mobility research has been sex-neutral. However, the study's cross-sectional design limits our ability to determine whether microbial changes precede or follow mobility decline, and replication across diverse populations remains essential.