Explanation
XYY Syndrome is a chromosomal variation in which males have an extra Y chromosome (47,XYY). Most individuals with this karyotype lead typical lives, often without noticeable differences. Early studies in the 1960s controversially suggested a link between XYY and increased aggression or criminality, fueling stigmatizing theories in biological criminology.
However, later research demonstrated these claims were flawed, based on biased samples (e.g., institutionalized populations). Contemporary genetics finds no direct causal connection between XYY and violent or criminal behavior. The debate over XYY Syndrome highlights the dangers of biological determinism, illustrating how simplistic genetic explanations can reinforce stereotypes and justify punitive policies.
In criminology, it serves as a cautionary tale against attributing complex social behaviors to genetic or biological factors alone.