Al-jawab billahi at-taufeeq (the answer with Allah's guidance)
Female circumcision is supported by no decisive textual evidence. Only male circumcision is practiced, due to the authentic evidence in the Sunnah that it is part of the natural way (Fitrah).
Female circumcision is simply a regional custom in the places where it is practiced. We must then take into consideration that many medical professionals consider it to have detrimental affects for the girls who undergo the operation. On that basis, it would be impermissible to allow this custom to continue. As, bringing harm to oneself is unlawful in Islam.
In a Hadith it is mentioned:
“Circumcision is Sunnah for men and an honorable thing for women.” [Musnad Ahmad (19794)]
Due to the weakness of this hadith and other Hadiths that refer to female circumcision – with some of their narrators being known for deceptiveness and others whose narrations carry no weight – scholars of Islamic Law have differed widely regarding its legal ruling.
1. In the Hanafî school of law, female circumcision is permissible within itself but not considered to be a Sunnah. (i.e. no religious virtue). (Shami Fatawaa Rahimiyyah, Page 261, Vol. 6)
2. It is considered a preferred act (Mandub) for women in the Maliki school of law. They rely upon the Hadith of Umm `Atiyyah for this ruling. ( Bulghah al-Salik li-Aqrab al-Masâlik and Ashal al-Madarik Sharh Irshad al-Salik)
3. In the Shaf'i school of law, circumcision is considered an obligation for both men and women. This is the official ruling of that school of thought. Some Shaf`i scholars express the view that circumcision is obligatory for men and merely Sunnah for women. ( al-Majmu`)
4. In the Hanbali school of law, circumcision is obligatory for men and merely an honorable thing for women. It is not obligatory for them. The Hanbali jurist Ibn Qudamah observes: “This is the view of many people of knowledge. Imam Ahmad said that it is more emphatic for men.” (al-Mughni (1/115))
Lastly, I would like to mention that there are no recorded evidences of circumcision done on the Prophet (Sallallahu alaihi wa sallam)'s daughters.
Please also refer to: http://qa.muftisays.com/index.php?viewpage=viewQA&question=1872
And Only Allah Ta'ala Knows Best