"Prohibited to you (For marriage) are:- Your mothers, daughters, sisters; father's sisters, Mother's sisters; brother's daughters, sister's daughters; foster-mothers (Who gave you suck), foster-sisters; your wives' mothers; your step-daughters under your guardianship, born of your wives to whom ye have gone in,- no prohibition if ye have not gone in;- (Those who have been) wives of your sons proceeding from your loins; and two sisters in wedlock at one and the same time, except for what is past; for Allah is Oft-forgiving, Most Merciful;" - Quran 4:23 (read more)

"Narated By Abdullah ibn Abbas : The Prophet (pbuh) said: If you find anyone doing as Lot's people did, kill the one who does it, and the one to whom it is done." - Tirmidhi 1457 (read more)

"Circumcision [of females] is not an inherited custom as some people claim, rather it is prescribed in Islam and the scholars are unanimously agreed that it is prescribed. Not a single Muslim scholar – as far as we know – has said that circumcision is not prescribed. Their evidence is to be found in the saheeh ahaadeeth of the Prophet (peace and blessings of Allaah be upon him), which prove that it is prescribed... Thus it is clear that the fuqaha’ of Islam are agreed that circumcision is prescribed for both males and females, and in fact the majority of them are of the view that it is obligatory for both. No one said that it is not prescribed or that it is makrooh or haraam." - Islam Q&A