This lecture explores the concept of parental investment, focusing on the importance of paternal involvement and the conflicts that arise within families due to genetic relatedness. It delves into topics such as altruism, kinship conflicts, and the impact of genetic proximity on altruistic behaviors. The discussion also covers the role of inclusive fitness in explaining altruism and the evolutionary theories behind parental investment. Additionally, the lecture examines real-life examples of parental behaviors, such as adoption practices and the allocation of resources based on genetic relatedness.