All Praise be to Allah Alone and peace and blessings be upon His Messenger, his family and Companions.
Circumcision is one of Sunan-ul-Fitrah (Islamic practices of personal hygiene) for both men and women. Du`ah (callers to Islam) should refrain from discussing circumcision when calling Kafirs (disbelievers) to Islam, if the idea is repulsive to them as Islam and `Ibadah (worship) are accepted from an uncircumcised person. After Islam settles in their hearts, they will realize why circumcision has been legislated.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.