sentences:  Subsequently, the World Health Organization promoted circumcision in high-risk populations as part of an overall program to reduce the spread of HIV, although some have challenged the validity of the African randomized controlled trials, prompting a number of researchers to question the effectiveness of circumcision as an HIV prevention strategy.The Male Circumcision Clearinghouse website was formed in 2009 by WHO, UNAIDS, FHI and AVAC to provide current evidence-based guidance, information, and resources to support the delivery of safe male circumcision services in countries that choose to scale up the procedure as one component of comprehensive HIV prevention services.In some cultures, males are generally required to be circumcised shortly after birth, during childhood or around puberty as part of a rite of passage.