AbstractAimPrevious studies reported that advanced paternal age (APA) may increase the risk of autism spectrum disorder (ASD) in offspring. However, effects of APA on behaviors have not been investigated in offspring of the same paternal mice. The present study sought to identify behavioral differences in mouse offspring of the same fathers at different paternal ages.MethodsWe assessed locomotor activity, anxiety‐like behavior, and social behavior in male mouse offspring that were born from the same fathers at three different paternal ages (3, 12, and 15 months old).ResultsNo differences in locomotor activity or anxiety‐like behavior were observed among any of the offspring groups. In the three‐chamber test, although the control group (3‐month‐old paternal age) exhibited significantly higher approach behavior toward the novel mouse compared with the novel object, the APA groups (12‐ and 15‐month‐old paternal ages) did not exhibit significant approach toward the novel mouse.ConclusionOffspring of 3‐month‐old fathers but not 12‐ or 15‐month‐old APA fathers exhibited social preference behavior. Although the present study was only exploratory, it demonstrated an interaction between social behavior and paternal age in offspring of the same paternal mice.