If a baby boy is born to a Jewish woman, but the boy isn't circumcised, is he still considered to be jewish?

Yes, an uncircumcised Jewish boy is still fully Jewish. Jewish identity (Jewishness) is determined by birth to a Jewish mother (or conversion), not by circumcision — a boy born to a Jewish mother is Jewish from the moment of birth, regardless of whether brit milah (circumcision) has been performed. However, failing to circumcise him is a serious violation of Torah law.

Key Takeaways

A boy born to a Jewish mother is Jewish from birth, regardless of circumcision status.
Brit milah (circumcision) is an obligatory mitzvah but does not determine Jewish identity.
The father has a Torah-level obligation to circumcise his son [Shulchan Aruch, Yoreh De'ah 260].
An uncircumcised Jewish male is called an arel (ערל) and faces the severe penalty of karet (spiritual excision) if he willfully remains uncircumcised as an adult.
Circumcision cannot be done on Shabbat unless it falls exactly on the eighth day from birth.

Jewish Identity vs. the Obligation of Circumcision

What Determines Jewish Identity?

The Talmud establishes the foundational principle that Jewish identity follows the mother [Kiddushin 68b]. This is derived from the verse in Deuteronomy 7:4, and is codified in the Shulchan Aruch [Even HaEzer 8:5].

A boy born to a Jewish mother is a full member of the Jewish people b'maziid — from the very moment of birth. There is no act he must perform to "become" Jewish; he already is.

Circumcision as Covenant, Not Criterion

*Brit milah is described in the Torah as the eternal sign of the covenant between God and the Jewish people:

"וְהָיְתָ֧ה בְרִיתִ֛י בִּבְשַׂרְכֶ֖ם לִבְרִ֥ית עוֹלָֽם" — "And My covenant shall be in your flesh as an everlasting covenant." [Genesis 17:13]

This verse makes clear that circumcision is the sign of the covenant — not the mechanism by which one enters the Jewish people. The covenant itself was established with Abraham and his descendants; the circumcision is its physical expression.

The Mitzvah Belongs Primarily to the Father

The Shulchan Aruch rules explicitly:

"מצות עשה לאב למול את בנו וגדולה מצוה זו משאר מצות עשה" — "It is a positive commandment for a father to circumcise his son, and this commandment is greater than other positive commandments." [Shulchan Aruch, Yoreh De'ah 260]

This means the primary obligation rests on the father, not the infant. An infant cannot be held halachically responsible for his own circumcision.

What Happens If the Father Fails?

If the father does not circumcise his son, the Beit Din (rabbinical court) bears responsibility to ensure it is done [Shulchan Aruch, Yoreh De'ah 261:1].
If no one performs it, when the boy becomes an adult (bar mitzvah at 13), the obligation falls upon himself.
If an adult male willfully refuses circumcision, he incurs the penalty of karet (כרת) — spiritual excision — as the Torah states: "וְעָרֵל זָכָר אֲשֶׁר לֹא יִמּוֹל אֶת בְּשַׂר עׇרְלָתוֹ וְנִכְרְתָה הַנֶּפֶשׁ הַהִוא מֵעַמֶּיהָ" — "An uncircumcised male who does not circumcise the flesh of his foreskin — that soul shall be cut off from its people." [Genesis 17:14]

Importantly, karet does not mean he stops being Jewish — it is a spiritual consequence, not a revocation of identity.

Timing: The Eighth Day

The Torah commands circumcision specifically on the eighth day:

"וּבַיּ֖וֹם הַשְּׁמִינִ֑י יִמּ֖וֹל בְּשַׂ֥ר עׇרְלָתֽוֹ" — "And on the eighth day, the flesh of his foreskin shall be circumcised." [Leviticus 12:3]

This obligation is so significant that it overrides Shabbat — but only when the eighth day falls naturally on Shabbat. If the circumcision is delayed past the eighth day for any reason, it may no longer be performed on Shabbat [Shabbat 132a].

Medical Exceptions

If a baby is ill or medically unfit for circumcision, Jewish law requires postponing it until the baby is healthy, because pikuach nefesh (preservation of life) overrides virtually all other commandments. The baby's Jewish identity remains completely intact during this time.

For personal guidance on any specific situation — including medical delays or any questions about performing a brit milah — consult your local rabbi or posek.