Wellbeing is one of a goal in development. Wellbeing that is represented by happiness. One determinant of happiness has children. Happiness is created through altruism. Parents care about their children's wellbeing, and their utility increases. Children's wellbeing is achieved when they have the high quality that enables them to percieved in the community. Happiness in this study is calculated using the happiness index. This study aims to find out the impact of children: number and sex composition of their children on parents happiness. Using the Indonesian Family Life Survey 2014 and multinomial logistic regression. The descriptive analysis shows that happiness will increase when men or women have one child, then the happiness level decreased as the increase in the number of children. Supporting the analysis, multinomial logistic regression shows that men who had children with either complete or incomplete sex composition are more likely to be happier than men who do not have children. Meanwhile, women will be happier if they have children with complete sex composition. However, multinomial logistic regression result shows that having more children significantly decreases the happiness level either in men or women.