The role of DNA evidence in sexual assault cases: A quantitative analysis of Turkish Supreme Court decisions (2015-2025).

This study examined the use of DNA analysis in Supreme Court rulings on a total of 556 sexual assault cases between January 1, 2015, and October 20, 2025, and investigated the impact of DNA analysis on conviction and acquittal outcomes. 40.28% of the cases were related to the crime of 'Aggravated Sexual Abuse of a Child'. A sharp increase in references to DNA evidence was observed from 2022 onwards. The Pearson Chi-Square test regarding DNA data in crimes committed against children and adults revealed a significant relationship between the variables (χ^2 = 17.539, p = 0.01599). The Pearson Chi-Square test between acquittal and conviction rates and the presence or absence of DNA also revealed a significant relationship between these variables (χ^2 = 9.4466, p = 0.006). Fisher's Exact Test, which examines the relationship between the presence of DNA (DNA present/absent) and the outcome of legal proceedings (conviction), revealed a statistically significant and strong negative correlation (OR: 0.13; 95% CI: 0.01-0.61; p = 0.0059). An Odds Ratio (OR) of 0.13 indicates that the odds of the 'target outcome' (conviction or acquittal) occurring in the presence of DNA evidence are 87% lower than in cases where DNA evidence is absent. DNA analyses constitute evidence with high probative value, significantly influencing both conviction and acquittal decisions in crimes against sexual integrity. However, the Supreme Court's jurisprudence indicates that DNA evidence alone is not always sufficient and must be evaluated in conjunction with other evidentiary elements.