Gender differences in labor markets and within households have been investigated by researchers for a long time. This dissertation adds new findings to the body of gender-related empirical studies on labor markets and demographic decisions. The first essay deals with the firm size selection behavior of workers and the firms' employment patterns by size in the United States. Using the Current Population Survey, I find that the changes in firm size distribution show different trends by gender between 1987 and 2001. While the percentage of female workers in large firms has increased gradually, that of male workers has hardly changed over time. These trends are not explained by changes in the distribution of demographic and job characteristics alone. I also find that the gender gaps in size-wage premia of workers in large firms decline over the period studied. Using these results, I show that gender wage convergence is partly accounted for by the changes in size distribution and size premia. The second essay examines how internet use affects job search and match outcomes of young workers in South Korea. Using the Youth Panel surveyed in 2001, I find that workers successfully employed through internet search have a significant wage premium over those employed through traditional methods, except for referrals or social networks. The positive wage effect is pronounced among women and previously unemployed workers. I also find that new employees who have ever searched online for jobs are more likely to search for other jobs. The third essay focuses on an idiosyncratic social norm and its effects on demographic outcomes. South Koreans have traditionally considered that the year of the Horse bears inauspicious implications for the birth of daughters. Using monthly longitudinal data at the region level between 1970 and 2003, I find that in the year of the Horse, the sex ratio at birth significantly increases while fertility decreases. The last essay examines how family cultural values, proxied by lunar calendar use for birthday, affect young individuals' marriage and fertility decisions in South Korea. Employing the Youth Panel, I find that young people with lunar birthdays, regardless of gender, are more likely to be married. More interestingly, young married men with lunar birthdays are more likely to have children, while young married women are not influenced by the tradition. These results are consistent with the hypotheses that young men from more traditional families enter into early marriages and that they are more likely to have offspring at earlier ages. / text