From the same link: >In humans, an association between the 2R allele of the VNTR region of the gene and an increase in the likelihood of committing serious cri

From the same link: >In humans, an association between the 2R allele of the VNTR region of the gene and an increase in the likelihood of committing serious crime or violence has been found. The VNTR 2R allele of MAOA has been found to be a risk factor for violent delinquency, when present in association with stresses, i.e. family issues, low popularity or failing school.[36][37][38][11] If any experts in this field are available to explain the discrepancy, I'd love to hear from them.