Background <p>Many studies have shown that stress before birth, like sleep deprivation (SD), affects a baby's brain and behavior. Most of these studies looked at mothers, but few have looked at fathers. This study looks at how sleep deprivation in father rats affects their offspring.</p> Methods <p>Adult male rats were deprived of rapid-eye movement (REM) sleep for 6&#xa0;h every day for 28&#xa0;days. After this period, they mated. We then studied the behavior and cognitive functions of their young rats using several tests. We also checked the levels of a brain chemical called BDNF in the hippocampus, a brain area important for learning and memory.</p> <p>Findings</p> <p>Father rats with sleep deprivation showed symptoms similar to mania in humans: they moved more, felt less anxiety, felt less pain, showed Obsessive–compulsive disorder (OCD)-like actions, climbed more, had memory problems, and had lower BDNF levels. Their children, both males and females, also showed most of these symptoms, but not changes in anxiety and OCD-like actions.</p> Conclusions <p>Lack of REM sleep in father rats can create a mania-like condition, and this affects their children's behavior and thinking skills.</p> Graphical Abstract <p></p>