本文運用傅科的有生權力概念，探察刑法妨害風化罪背後的性價值體系所涉及的社會進化論與法益界線。在20世紀初期，德國科學研究者曾運用一套特定的優生學論述，促使國家積極管制女人與兒童的性，以強化集體「效益」。作為一種生物決定論，它的核心概念是總人口的健康超越個人的利益。立基於此概念，性被用來作為退化的主要指標，根據性反常、遺傳與退化的相互關連，從德國到歐美許多國家，乃至於1920年代的中國，都以刑法的妨害風化罪章則作為性管制的工具。然而，國家制度的功能必須是客觀的，猥褻或不道德的行為不能因特定群體的利益而遭受刑事懲戒，必須以特定法益受到侵害為前提。倘若欠缺所要保護的法益，立法者不得恣意創設「構成要件」。台灣現行的妨害風化罪條款真能符合刑法維護法益的比例原則嗎？所謂的社會風化，難道不正是為了實現以「種族化的身體」為核心概念所形成的性價值體系？

This article uses the Foucauldian concepts of “biopolitics,” in company of the discourse of eugenics, to study the historical developments of views on sex crimes in Taiwan. Toward the beginning of the 20th century, with an increasing interest in sexual politics associated with genetic findings, the “gender order” of eugenics and medical knowledge entered the German political arena. The anxieties about perversion-heredity-degeneration demanded the political managements not only of woman’s sexuality. But to control “abnormal” sex drives, the criminal systems also came to severely regulate sexual behavior, aiming at the exclusion of the underprivileged and enforcing a return to sexual morality. Consequently, in the 1920s, eugenics and sex hygiene facilitated the national regulation of gender/sexuality in China, whose legal system Taiwan inherited. However, the later critical developments in Germany prompt us to ask: how far should the state intervene in the sexual lives of its citizens? Contrasting this critical thinking with the strategies and rhetoric of regulating sexuality in Taiwan, what is really necessary now is to bring the eugenic dynamics behind criminal law into a sharper view for examination.