Complex sentence: Although many of the medical benefits of circumcision have been debunked as myths, a 2005 study in Africa indicated that circumcised men had a 70% lower chance of contracting HIV when having sex with infected women, when compared with uncircumcised men.
Split into simpler sentences: Although many of the medical benefits of circumcision have been debunked as myths, there is evidence that circumcision can have real medical benefits. A 2005 study in Africa indicated that circumcised men had a 70% lower chance of contracting HIV when having sex with infected women, when compared with uncircumcised men.