There are a considerable number of cases reported that an ex-convict's children are negatively perceived even though they themselves have not committed a crime. However, there are few quantitative researches and reasons for the negative perception have not been discussed well. This study hypothesized that the negative perception is associative stigma, and a reason for the stigma is genetic essentialism. Associative stigma is the tendency to being stigmatized or devalued based on his or her association with a stigmatized person. Genetic essentialism is the tendency to ascribe genes as a fixed and underlying nature to members of a category. An experiment was conducted, where all the participants were shown two separated vignettes of a middle-aged man who was a murderer, and of a boy who slapped his classmate. Also, the participants were given a minimum amount of information about the relationships between the two protagonists; they were randomly divided into three conditions, Child-by-blood condition (CBB), Child-by-adoption condition (CBA), and Unrelated condition (URL). If the hypothesis is supported, the boy would be perceived negatively most by CBB and least by URL. The results showed that while the boy was perceived more negatively by CBB than by URL when the perception of the middle-aged man, the murderer, was controlled, there was no such difference between CBA and URL. Although there was no difference between CBB and CBA, which contradicts with the hypothesis that genetic essentialism is a reason for the stigma, considering that there was a significant difference only between CBB and URL and not between CBA and URL, there is the possibility of the existence of genetic essentialism.