It is well known that circumcision is an act pertaining to the fitrah (pure human nature). Some Muslim scholars consider it as a confirmed Sunnah. Other scholars consider it mandatory.
“First of all, we would like to stress the fact that circumcision is the Sunnah of Prophet Ibrahim and Prophet Muhammad (peace and blessings be upon them all). Prophet Muhammad (peace and blessings be upon him) is reported to have said, “Five are the acts quite akin to fitrah: Circumcision, shaving the pubes, cutting the nails, plucking the hair under the armpits and clipping (or shaving) the moustache.” (Reported in all the six authentic collections of Hadith)
As regards the juristic views on this, Imam Abu Hanifah and Imam Malik maintain that circumcision is considered as a confirmed Sunnah (Sunnah Mu’akkadah), whereas Imam Shafi`i and Ahmad ibn Hanbal see it as mandatory (wajib).

Circumcision in Medical Perspectives:

Circumcision, being an act of fitrah, reflects Islam’s keenness on preserving man’s health and personal hygiene. This is further clarified in the following:

Circumcision is a universal practice which is greatly influenced by cultural and religious traditions. It is the most frequent operation on males not only in Islamic countries, but also other parts of the world. For example, in the United States of America more than one million male infants are circumcised each year. The performance of circumcision is one of the rules of cleanliness in Islam.
The word fitrah in relation to cleanliness can refer to the Sunnah of the Prophet (peace and blessings be upon him), with regard to this matter, and fitrah also ‘implies an inner sense of cleanliness in man which is proof of his moral convictions and mental health.’

Male circumcision means removal of the foreskin of the penis. The Islamic scholar Al-Mawardi said, ‘The ideal method is to remove the skin completely from the beginning of the glans, and the minimum condition is that nothing is left to cover the end of the glans.” The Prophet (peace and blessings be upon him) recommended performing circumcision at an early age. Al- Mawardi stated that the chosen time is the 7th day after birth, but it can be carried out up to 40 days after birth or thereafter until the age of 7 years, depending upon the health of the infant or child at the time.

There is an ongoing debate on the value of neonatal circumcision. Indeed, the position of the American Academy of Pediatrics since 1975 has been that there are no valid or absolute medical indications for routine circumcision of newborn male infants. On the other hand, the results of recent clinical and epidemiological studies are supportive of the practice of circumcision in newborn and infant males. From a two-part study involving cohorts of 3,924 and 422,328 infants respectively Wiswell and Roscelli found a higher rate of urinary tract infection in uncircumcised compared with male circumcised infants. These investigators observed that as the circumcision frequency rate decreases, the incidence of urinary tract infections increases. Infection usually begins in the foreskin which becomes swollen and difficult to retract. A medium for bacterial growth and further spread of infection is provided by the fecal material trapped between the foreskin and glans of the penis. Such a condition probably leads to other more serious complications.

Proper hygienic care of the penis, which includes regular washing, will prevent some infections, but among children this is difficult to maintain and is probably not as effective as circumcision. Some conditions, such as phimosis, often lead to circumcision at a later age that could have been prevented if it had been performed earlier. The possible risk for long term urological complications in the infected, uncircumcised male infant has not been properly studied. It is known, however, that as many as 50% of male infants with urinary tract infections will subsequently reveal demonstrable radiologic abnormalities. Thus, the performance of circumcision and the practice of sunan Al-fitrah as recommended in Islam is medically beneficial and reflects the wisdom of the Islamic statements.”