The prevalence of adult overweight and obesity has increased substantially in the United States over the past few decades. Besides the health consequences of obesity, it also has social and psychological consequences. As a social marker, it influences individuals' positions or status in a various social contexts and thereby contributes to social stratification. Using The National Longitudinal Study of Adolescent Health (Add Health) data, this paper analyzes the effect of obesity on the likelihood and timing of union formation (marriage and cohabitation) among young adults. The research questions are: Does obesity affect union formation such as cohabitation and marriage? If obesity affects union formation, what are the mechanisms through which it does so? We found that before controlling possible confounding variables, obese young adults will have lower likelihood of entering cohabitation and marriage. After controlling those variables, the difference between obese and non-obese young adult becomes non-significant, but those who are over weighted have higher likelihood to marry and cohabit
