(Continued from here: I, II, III, IV)
I don't know how I missed this release from the RCA, dated June 7, 2005:
It is well known that there is a dispute among poskim regarding the obligation to engage in metzitza be'peh. Four major viewpoints exist, and we provide some sources for each below. More complete reviews are summarized in many sources, including Nishmat Avaraham, Vol. 2., Yoreh De'ah 263:8 (p. 176) and 264:5 (pp. 182-183), and elsewhere.
The first view is that of Tiferet Yisrael (Commentary to Mishnah Shabbat 19:2), who regards metzitza as strictly a medical matter. The Talmud requires metzitza to avoid medical danger. Even though Tiferet Yisrael affirms that doctors in his day stated that this danger no longer exists (in keeping with the principle of nishtaneh ha'teva) and that, to the contrary, the act of metzitza itself might pose potential danger to the child, Tiferet Yisrael nonetheless advocated metzitza be'peh because he believed that doctors of his day agreed that it also provided a medical benefit to the child.
The second view is that metzitza is required and may be performed with any device - mouth or even sponge - that draws blood from the wound. (Chatam Sofer cited in Rav Pirutinsky's Sefer Habrit, pp. 216-217).
The third view is that metzitza be'peh is required, but the requirement of be'peh may be fulfilled through suction generated by the mouth through a tube. (Proclamations by Rabbi A. Hildesheimer and Rabbi S. R. Hirsch to their respective communities, and the latter's Responsa Shemesh Marpeh 55; Rabbi Tzvi Pesach Frank, Responsa Har Tzvi 214; Rabbi A. Y. Hakohen Kook, Responsa Da'at Kohen 142; others cited in addendum to p. 222 at back of Sefer Habrit).
The final view is that metzitza be'peh actually requires suction from the mouth directly onto the site of the circumcision. (Responsa Binyan Tziyon 1:23-24; Responsa Maharam Schick Orach Chaim 152; Responsa Avnei Neizer 1:338).
The poskim consulted by the RCA (Rabbi Gedalia Dov Schwartz, Av Beit Din of the Beth Din of America and of the Chicago Rabbinical Council; Rabbi Hershel Schachter of RIETS/YU and the Union of Orthodox Congregations of America; and Rabbi Mordechai Willig of RIETS/YU and Segan Av Beit Din of the Beth Din of America) agree that the normative halacha undoubtedly permits the third view, and that it is proper for mohalim to conduct themselves in this way given the health issues involved in the fourth view. Rabbi Schachter even reports that Rav Yosef Dov Soloveitchik reports that his father, Rav Moshe Soloveitchik, would not permit a mohel to perform metzitza be'peh with direct oral contact, and that his grandfather, Rav Chaim Soloveitchik, instructed mohelim in Brisk not to do metzitza be'peh with direct oral contact. However, although Rav Yosef Dov Soloveitchik also generally prohibited metzitza be'peh with direct oral contact, he did not ban it by those who insisted upon it, and neither does the RCA advocate any such ban. Those who wish to follow their customs in accordance with the above-noted authorities are certainly entitled to do so, but the RCA is firmly of the opinion that in light of current realities and medical knowledge it is proper, and preferable, to use a tube.