Female circumcision is a terrible thing, but it's not true to say that "it increases the risk of HIV transmission". It actually seems to decrease the risk.
The 2005 Stallings study showed the following:
Results: In the final logistic model, circumcision remained highly significant [OR=0.60; 95% CI 0.41,0.88] while adjusted for region, household wealth, age, lifetime partners, union status, and recent ulcer.
Conclusions: A lowered risk of HIV infection among circumcised women was not attributable to confounding with another risk factor in these data.