生育活动的私密性和人口的高度流动性致使国家对生育的干预成本过高,并存在技术障碍,这就使得国家只能通过对结婚行为的否定来达到防止近亲生育的目的。国家通过宣告婚姻无效,从而瓦解婚姻世界所必需的信任,进而迫使婚姻双方产生不信任,最终实现对近亲鸳鸯的社会控制。宣告婚姻无效这一私法技术是一种无需成本的控制方式,故对国家极具吸引力。但是,立法者在得益于无效等私法控制技术无成本的实惠之时,也应正视私法控制技术的不足及潜在危险。 The confidentiality of childbearing activities and the high mobility of population make the intervention cost of the state too high and there are technical obstacles, which makes the country only achieve the purpose of preventing the birth of relatives through negating the marriage behavior. By announcing the ineffectiveness of the marriage, the state has crushed the trust necessary for the world of marriage, thereby forcing the two sides of the marriage into mistrust and eventually realizing the social control of the close relatives. Declaration of Invalid Marriage This private-law technique is a cost-free method of control and is therefore attractive to the nation. However, when legislators benefit from non-cost-effective benefits such as ineffective private-law control, they should also address the shortcomings and potential dangers of private-law control technologies.