The study was done on heterosexuals in the USA. Google 'Circumcision prevents HIV' 'Circumcision does not prevent HIV' or 'Circumcision STDs' and you will get all the info. You will find why American Medical associations do not support circumcision as a way to prevent infections. HIV is from fluid transfer. Anal sex might have more chafing and thus more transfer. There is dry sex in Africa that is causing more HIV infections. Personaly I don't think there is much of a difference. Would I be afraid of sexua| contact with a woman who had HIV even though there is less chafing? Yes, absolutely.