Circumcision is mandatory for Muslims based on tradition, but it is not mentioned in the Qur'an itself. The following section is found in the standard Shafi'i manual of Islamic law: (Book E - "PURIFICATION e4.3 Circumcision is obligatory (O: for both men and women. For men it consists of removing the prepuce from the penis, and for women, removing the prepuce (Ar. bazr) of the clitoris (n: not the clitoris itself, as some mistakenly assert). (A: Hanbalis hold that circumcision of women is not obligatory but sunna, while Hanafis consider it a mere courtesy to the husband.)

The Muslim obeys the command of Allah. This is the meaning of Islam, which is submission to Allah and obedience to His command, whether the wisdom behind it is clear to him or not, because the One Who is issuing the command - Allah, may He be exalted - is the Creator, the All-Knowing, the All-Aware, who created mankind and knows what is good for them and what is not good for them. Circumcision is one of the rulings of sharee'ah which the Muslim carries out willingly, in submission to and out of love for Allah, and seeking reward with Him. He is certain that Allah does not command anything unless there is a wisdom behind it and it is good for His slaves, whether people know that or not. Since your question referred to the health benefits of circumcision, we will, after looking at the shar'i (religious) benefits, will answer your question about the health benefits, in order to increase the believers in faith in the ruling, and so that non-Muslims may see one aspect of the greatness of this sharee'ah (Islamic law) which came to bring benefits and ward off harm.

Circumcision is one of the commands concerning beautification enjoined by Allah, which Allah has prescribed for His slaves to make them beautiful both outwardly and inwardly (physically and spiritually). It is the perfection of the fitrah (natural state of man) with which He created them, and hence it is the perfection of the haneefiyyah (pure monotheism) of the religion of Ibraaheem (Abraham). The origin of the institution of circumcision as the perfection of haneefiyyah was when Allah made a covenant with Ibraaheem and promised to make him an imam (leader) of mankind, and promised him that he would be the father of many people, that prophets and kings would come from his loins and that his descendants would be many. And He told him that between him and his descendants there would be the sign of the covenant, which would be that every newborn male among them would be circumcised, and so the covenant would have this sign on their bodies. Circumcision is a sign of having entered into the religion of Ibraaheem, and this is in accordance with the interpretation of the verse (interpretation of the meaning) -

"[Our Sibghah (religion) is] the Sibghah (religion) of Allah (Islam) and which Sibghah (religion) can be better than Allaah's? And we are His worshippers" [al-Baqarah 2:138] -

For the haneefs (pure monotheists, i.e., Muslims), circumcision has the same status as baptism does for the worshippers of the cross (i.e., Christians). They purify their children - as they say - when they baptize them in the baptismal water, and they say; now he has become a Christian. Allah has prescribed for the haneefs their own rite, the symbol of which is circumcision. Allah says (interpretation of the meaning): "[Our Sibghah (religion) is] the Sibghah (religion) of Allah (Islam) and which Sibghah (religion) can be better than Allaah's? And we are His worshippers"
[al-Baqarah 2:138] - So Allah has made circumcision a symbol of those who belong to Him and to His religion, and who attribute themselves to Him as being utterly enslaved to Him alone…

It is not essential for the child to remain as he is when he comes forth from his mother's womb, if there is something that may be done for him that serves a purpose and is enjoined by the pure religion. Such things include shaving his head after he is born, because that is in his best interests. The Prophet of Islam (peace and blessings of Allah be upon him) said: "Remove the harm from him." The same applies to washing the blood from him and cutting the cord by which he was attached to his mother, and other things which are done to benefit him.