I'll tell you the real reason. It is to prevent the need to do so later in life if you do develop problems. It is much more traumatic to have it done as an adult than as a newborn. Newborns are already going through the trauma of birth, so the operation really doesn't add that much trauma. There are many reasons that it can become neccessary as an adult. Having it done as an adult is extremely painful and takes about a month to get over. This is not what I've heard. I know. Catch my drift? I always thought I would never have it done to my own sons, until I went through it as an adult. Trust me, its better as a newborn.

From Jewfaq: Of all of the commandments in Judaism, the brit milah (literally, Covenant of Circumcision) is probably the one most universally observed. It is commonly referred to as a bris (covenant, using the Ashkenazic pronunciation). Even the most secular of Jews, who observe no other part of Judaism, almost always observe these laws. Of course, until quite recently, the majority of males in the United States were routinely circumcised, so this doesn't seem very surprising. But keep in mind that there is more to the ritual of the brit milah than merely the process of physically removing the foreskin, and many otherwise non-observant Jews observe the entire ritual. The commandment to circumcise is given at Gen. 17:10-14 and Lev. 12:3. The covenant was originally made with Abraham. It is the first commandment specific to the Jews. Circumcision is performed only on males. Although some cultures have a practice of removing all or part of the woman's clitoris, often erroneously referred to as "female circumcision," that ritual has never been a part of Judaism. Like so many Jewish commandments, the brit milah is commonly perceived to be a hygienic measure; however the biblical text states the reason for this commandment quite clearly: circumcision is an outward physical sign of the eternal covenant between G-d and the Jewish people. It is also a sign that the Jewish people will be perpetuated through the circumcised man. The health benefits of this practice are merely incidental. It is worth noting, however, that circumcised males have a lower risk of certain cancers, and the sexual partners of circumcised males also have a lower risk of certain cancers. The commandment is binding upon both the father of the child and the child himself. If a father does not have his son circumcised, the son is obligated to have himself circumcised as soon as he becomes an adult. A person who is uncircumcised suffers the penalty of kareit, spiritual excision; in other words, regardless of how good a Jew he is in all other ways, a man has no place in the World to Come if he is uncircumcised. Circumcision is performed on the eighth day of the child's life, during the day. The day the child is born counts as the first day, thus if the child is born on a Wednesday, he is circumcised on the following Wednesday. Keep in mind that Jewish days begin at sunset, so if the child is born on a Wednesday evening, he is circumcised the following Thursday. Circumcisions are performed on Shabbat, even though they involve the drawing of blood which is ordinarily forbidden on shabbat. The Bible does not specify a reason for the choice of the eighth day; however, modern medicine has revealed that an infant's blood clotting mechanism stabilizes on the eighth day after birth. As with almost any commandment, circumcision can be postponed for health reasons. Jewish law provides that where the child's health is at issue, circumcision must wait until seven days after a doctor declares the child healthy enough to undergo the procedure. Circumcision involves surgically removing the foreskin of the penis. The circumcision is performed by a mohel (lit. circumciser; rhymes with oil), a pious, observant Jew educated in the relevant Jewish law and in surgical techniques. Circumcision performed by a regular physician does not qualify as a valid brit milah, regardless of whether a rabbi says a blessing over it, because the removal of the foreskin is itself a religious ritual that must be performed by someone religiously qualified. If the child is born without a foreskin (it happens occasionally), or if the child was previously circumcised without the appropriate religious intent or in a manner that rendered the circumcision religiously invalid, a symbolic circumcision may be performed by taking a pinprick of blood from the tip of the penis. This is referred to as hatafat dam brit. While the circumcision is performed, the child is held by a person called a sandek. In English, this is often referred to as a godfather. It is an honor to be a sandek for a bris. The sandek is usually a grandparent or the family rabbi. Traditionally, a chair (often an ornate one) is set aside for Elijah, who is said to preside over all circumcisions. Various blessings are recited, including one over wine, and a drop of wine is placed in the child's mouth. The child is then given a formal Hebrew name. It is not necessary to have a minyan for a bris, but it is desirable if feasible. As with most Jewish life events, the ritual is followed by refreshments or a festive meal. The Circumcision Controversy In recent times, circumcision has become controversial. Some have hypothesized that infant circumcision has harmful psychological effects and may cause sexual dysfunction. Many websites have sprung up promoting this point of view, and even in Israel there are those who want to outlaw circumcision as child abuse. To the best of my knowledge, there is no concrete, scientific evidence that circumcision has any harmful effect. The rate of complications from circumcision is one of the lowest of all surgical procedures, and the most common complication is simply excessive bleeding. At most, the latest scientific evidence indicates that the health benefits of circumcision are not as great as previously assumed, thus there is no reason to perform routine circumcisions for the purposes of hygiene. However, as stated above, Jewish circumcision is not performed for the purpose of hygiene. From the traditional Jewish point of view, there is no controversy. The ritual of circumcision was commanded by our Creator, and He certainly knows what is and is not good for us. The G-d who commanded us not to harm ourselves certainly would not command us to do something harmful to ourselves, and even if He did, the observant Jew would nonetheless heed His wishes. For more information on the traditional Jewish response to the circumcision controversy, see Bris Milah: Beautiful or Barbaric? at Aish ha-Torah's website.

Yes I do belive that it should stay where it was put ... I dont belive in circumcision.. but thats just me !

Most people and cultures in the world don’t circumcise their infants or children, in cultures that do circumcise it is for religious and cultural reasons. The practice is so old that the real reason’s have little to do with today’s religions, again this practice outdates even Judiasm which is the oldest religion that requires circumcision. As for hygiene , many intact cultures have better health and fewer STD’s when compared to circumcising countries like the US, so the proof of it having some medical benefit/s seem to be missing.

Removing the foreskin prevents infection like UTI because bacteria grow in moist environments.

Yes, it should stay right where it was when he was born. They are cutting off the most sensitive part of the glans. and there is no need to whack it off. It doesn't get all unsanitary if the guy just bathes like a normal person.