Second Proposal—How the System of Mandatory Married Couples' Shared Surnames Accelerates Declining Birthrates—

This proposal highlights the structural problem that Japan’s mandatory single-surname system for married couples undermines women’s dignity and discourages marriage, thereby accelerating the decline in birthrates. Requiring one partner—most often women—to give up their family name strips away personal identity and creates unconscious psychological pressure, leading to marriage avoidance and lower fertility. While this issue is specific to Japan, it demonstrates more broadly how “institutional assimilation” can restrict individual freedom and negatively influence demographic trends. The proposal calls for the adoption of an optional separate-surname system and reforms to marriage institutions in order to safeguard individual dignity and restore social sustainability.