Medical Benefits of Female Circumcision in Islam
Question

Could you explain to me what is the medical benefit of a girl’s circumcision?
Praise be to Allah.Islamic Guidance on Human Welfare and Obedience
Just as Allah has created mankind, He has also guided them that which is best suited to their interests in this world and in the Hereafter, so He sent them Messengers and revealed Books to guide mankind to what is good and urge them to follow it, and to teach them what is evil and warn them against it.
Islam may enjoin or forbid something and the people – or most of them – may not be able to see the wisdom behind this command or prohibition. In that case we are obliged to obey the command or heed the prohibition and to have certain faith that the laws of Allah are all good, even if we cannot see the wisdom behind them.
Circumcision in Islam: A Sunnah of the Fitrah
Circumcision is one of the Sunnahs of the Fitrah, as is indicated by the words of the Prophet (peace and blessings of Allah be upon him): “The Fitrah is five things – or five things are part of the fitrah – circumcision, shaving the pubes, plucking the armpit hairs, cutting the nails, and trimming the moustache.” (Narrated by Al-Bukhari, 5889 and Muslim, 257)
Undoubtedly with regard to the Sunnahs of the Fitrah, some of the wisdom behind them is obvious, and that includes circumcision. There are clear benefits to it which we should pay attention to and understand the wisdom behind it.
In the answer to question no. 9412 we have discussed circumcision, how it is to be done and the ruling on it. In the answer to question no. 7073 we have explained the health and Shar`i benefits of circumcision for males.
Is Female Circumcision Obligatory?
Circumcision is prescribed for both males and females. The correct view is that circumcision is obligatory for males and that it is one of the symbols of Islam, and that circumcision of women is recommended but not obligatory.
There are reports in the Sunnah which indicate that circumcision for women is prescribed in Islam. In Madeenah there was a woman who circumcised women and the Prophet (peace and blessings of Allah be upon him) said to her: “Do not go to the extreme in cutting; that is better for the woman and more liked by the husband.”  (Narrated by Abu Dawud, 5271; classed as authentic by Shaykh Al-Albani in Sahih Abu Dawud)
Health Benefits of Female Circumcision in Islam
Female circumcision has not been prescribed for no reason, rather there is wisdom behind it and it brings many benefits.
Mentioning some of these benefits, Dr. Hamid Al-Ghawabi says:
The secretions of the labia minora accumulate in uncircumcised women and turn rancid, so they develop an unpleasant odour which may lead to infections of the vagina or urethra. I have seen many cases of sickness caused by the lack of circumcision.

Circumcision reduces excessive sensitivity of the clitoris which may cause it to increase in size to 3 centimetres when aroused, which is very annoying to the husband, especially at the time of intercourse.
Another benefit of circumcision is that it prevents stimulation of the clitoris which makes it grow large in such a manner that it causes pain.
Circumcision prevents spasms of the clitoris which are a kind of inflammation.
Circumcision reduces excessive sexual desire.

Misconceptions and Clarity on Female Circumcision
Then Dr. Al-Ghawabi refutes those who claim that female circumcision leads to frigidity by noting:
Frigidity has many causes, and this claim is not based on any sound statistics comparing circumcised women with uncircumcised women, except in the case of Pharaonic circumcision which is where the clitoris is excised completely. This does in fact lead to frigidity but it is contrary to the kind of circumcision enjoined by the Prophet of mercy (peace and blessings of Allah be upon him) when he said: “Do not destroy” i.e., do not uproot or excise. This alone is evidence that speaks for itself, because medicine at that time knew very little about this sensitive organ (the clitoris) and its nerves. (From Liwa’ Al-Islam magazine, issue 8 and 10; article entitled Khitan Al-Banat (circumcision of girls))
The female gynaecologist Sitt Al-Banat Khalid says in an article entitled Khitan Al-Banat Ru’yah Sihhiyyah (Female circumcision from a health point of view):
For us in the Muslim world female circumcision is, above all else, obedience to Islam, which means acting in accordance with the fitrah and following the Sunnah which encourages it. We all know the dimensions of Islam, and that everything in it must be good in all aspects, including health aspects. If the benefits are not apparent now, they will become known in the future, as has happened with regard to male circumcision – the world now knows its benefits and it has become widespread among all nations despite the opposition of some groups.
Then she mentioned some of the health benefits of female circumcision and said:

It takes away excessive libido from women
It prevents unpleasant odours which result from foul secretions beneath the prepuce.
It reduces the incidence of urinary tract infections
It reduces the incidence of infections of the reproductive system.

In the book on Traditions that affect the health of women and children, which was published by the World Health Organization in 1979 it says:
With regard to the type of female circumcision which involves removal of the prepuce of the clitoris, which is similar to male circumcision, no harmful health effects have been noted.
And Allah knows best.