Why is it important to circumcise Jewish babies?

Circumcision is a religious tradition for Jews that goes back thousands of years. No one knows for sure how it started, but it is believed it may be related to difficulties with hygiene in the desert environment of the Middle East. Jewish theologians generally discount the practical explanation in favor of the religious one.

The Jewish bris is a sign of Abraham's covenant with G-d. It is practiced by all branches of Judaism. The reason male circumcision is important to Judaism is because the Torah specifies that uncircumcised Jewish males are cut of from Judaism and cannot participate in a large percentage of Jewish life and ritual.

In terms of when the circumcision occurs, aside from the Torah specifying it must be done at 8 days, modern research has shown that blood clotting performance peaks at 8 days. Additionally, when circumcision is done at 8 days, it is a minor process that heals within 36-48 hours on average. Adult male circumcision is a serious surgery that requires stitches and a fairly long and painful healing process.