Genesis: 17:13 –Those born in the house and those purchased for money shall be surely circumcised (המול ימול), and My covenant shall be in your flesh as an everlasting covenant.
Babylonian Talmud – Avodah Zara 27a: – It was taught as follows: From what verse do we know that it is invalid for a non-Jew to perform a circumcision on a Jew? From the verse that states “shall be surely circumcised…”
Torah Temimah Colloquial Translation on Note #36:
It is possible that the exegesis is from the word “ המול” and is taken to allude to the idea of “מהול“– one who is circumcised. This is done by swapping the first two letters of the word with each other as we find is sometimes done in rabbinic discussions. Thus, the meaning would be “one who is circumcised should perform the circumcision”. In a previous verse (Genesis 17:9) a similar lesson is learned from the phrase “And you, my covenant shall you keep” – “you and people similar to you”. See there for a fuller explanation.
The Gemora explains that there is a practical halachic ramification that depends on which verse is used as the source. The halachic difference being whether women are allowed to perform circumcisions or not. If you deduce the rule from the verse “And you, my covenant shall you keep” – then a woman would not be allowed to perform circumcisions because she isn’t included in the “covenant of circumcision”. However, if you deduce the rule from our verse of “shall be surely circumcised (המול ימול)” – then the principle of “woman are considered as circumcised” would apply. Look over there are the pertinent Gemora and Tosafot.
Note that we hold as a matter of law that women are permitted to perform circumcisions. This is the conclusion of the Gemora based on the verse in Exodus 4:25 “Tzipporah took a sharp stone and cut off the foreskin of her son”. (Note that according to those of the opinion that women are not allowed to perform circumcisions, they understand this verse to mean that Tzipporah began the circumcision, but Moshe completed it.)
In Yoreh Deah section 264 [Yosef Karo] states explicitly that a woman is permitted to perform circumcisions with the condition that if there is a Jewish man of greater stature who knows how to perform circumcisions, then that person would have preference. The Ramah [famous Askenazic early halachic authority] states there, “there are those who say that a woman should not perform circumcisions and our custom is to seek a man to be the mohel.” The Shach and the Gra wonder about the comment of the Ramah and believe that his comment was self-evident and wonder why he commented.
It appears that the intent of the Ramah’s comments is that one is obligated to seek a man to be the mohel even if there is not one close by. This would be in contrast to the opinion of Yosef Karo who would only give precedence to a man if he were present and able to perform the circumcision but there would be no obligation to seek out a man as a mohel.
The logic of the Ramah is that he [essentially] was of the opinion that a woman is not allowed to perform circumcisions. However, the obligation of performing the circumcision on the 8th day takes precedence since the core halacha is that a woman is allowed to perform the circumcision. In spite of this fact, the Ramah’s opinion is that one should seek out a man to perform the circumcision in order to comply with the stricter opinion that a woman may not perform the circumcision.
Additionally, regarding the Shach’s comment that the Ramah stated an obvious fact “we are accustomed to seek a man to perform the circumcision” since a woman is not commonly found who can perform circumcisions, that is not a valid critique by the Shach. If it were decided that a woman is allowed to perform circumcisions even in a situation where a competent male was present, then it is probable that then more woman would learn this skill. From the decision that they are not allowed to perform circumcisions, that is why they have not learned this skill.
Translator’s Note: I appreciated the Torah Temimah’s analysis of the Shach’s observation that there are very few women who have this skill.