For a study, it was determined that a growing body of research suggested that psychopathological diseases were linked to the gut microbiome. However, long-term longitudinal birth cohorts, particularly those including low-risk healthy individuals, have a shortage of data. As a result, the researchers sought to describe the evolution of the gut microbiota in healthy children from birth to age 10 and to look into any links between internalizing and externalizing behavior. Furthermore, 16S ribosomal RNA gene sequencing was used to examine the fecal microbial makeup of participants in an ongoing longitudinal study (N=193) at 1, 3, and 4 months and at 6 and 10 years of age. Therefore, 3 clusters were found in infancy based on these data, 2 of which were dominated by Bifidobacterium. About 4 clusters were identified in childhood, 2 of which became more prevalent with maturity. Prevotella 9 was considerably enriched in 1 of the childhood clusters, akin to an enterotype. Breastfeeding had significant effects on microbiota composition until the age of 10, showing that it played a more extended role in developing gut microbial ecology. Behavior was not linked to microbial groupings. Prevotella 9 in childhood, on the other hand, was related to mother-reported externalizing behavior at the age of 10, which was confirmed by child accounts. Previous outcomes on Bifidobacterium-enriched and -depleted clusters in infancy were established in the investigation. It also charted the continuous evolution of the gut microbiota in middle childhood, which was significant. There were new links discovered between gut microbial composition in the first 10 years of life (particularly Prevotella 9) and externalizing behavior at age 10. Replications will determine the significance of the findings in additional cohorts and follow-up assessments.