The following is a list of notable halachic rulings by Rabbi Moshe Feinstein, the foremost halachic authority of the late 20th century in the United States; ResponsainIgrot Moshe are cited in parentheses.
Bat Mitzvah for girls (OH I:104 (1956), OH II:97 (1959), OH IV:36)[4]
Brain death as an indication of death under Jewish law. (YD II:146,174, III:132, IV:54)[5] However, this is disputed.
Cholov Yisroel Permitted reliance (at least under extenuating circumstances, such as if no Cholov Yisroel milk is available[6]) on U.S. government agency supervision in ensuring that milk was reliably kosher, and it is as if Jews had personally witnessed it (YD I:47). This was a highly controversial ruling disputed by prominent peers of Feinstein.[7]
Separation of conjoined twins who were fused all the way from the shoulder to the pelvis and shared one heart. It is during this case that C. Everett Koop, the 13th Surgeon General of the United States, said "The ethics and morals involved in this decision are too complex for me. I believe they are too complex for you as well. Therefore I referred it to an old rabbi on the Lower East Side of New York. He is a great scholar, a saintly individual. He knows how to answer such questions. When he tells me, I too will know."[12]
Shaking hands between men and women (OH I:113; EH I:56; EH IV:32)[13]
^Rav Yaakov Breisch in Chelkas Yaakov Vol.2 ch.37 stated that "all of his rationales are not sufficient to contradict a clear ruling of the Shulchan Aruch and halachic authorities...." Later in ch.37 and 38, Breisch extensively disputes various premises underlying the rationale for Feinstein's lenient ruling. See also Shu"t Beer Moshe Vol.4, ch.52, Kinyan Torah 1:38 for a more detailed listing of the many authorities disputing Feinstein's reasoning and conclusion.
^פיינשטיין, משה. אגרות משה חלק ז - חושן משפט חלק שני סימן ל. p. 244. Retrieved 12 November 2017. הנה בדבר שאלתו על כותב האג״מ מה ששמע שבישיבות מתירין להתלמידים לגנוב את התשובות להשאלות במבחני הסיום שעושה המדינה (רידזענם) 'כדי להונות ולקבל את התעודות שגמרו בטוב, הנה דבר זה איסור לא רק מדינא דמלכותא אלא מדין התורה, ואין זה רק גניבת דעת שג״כ אסור כדאמר שמואל בחולין דף צ״ד ע״א שאסור לגנוב דעת הבריות ואפילו דעתו של עכו״ם וכ״ש הכא שהוא גניבת דעת לכולי עלמא אף לישראל, אלא 'דהוא גם גניבת דבר ממש דהא כשירצה לפרנסתו במשך הזמן להשכיר עצמו
^See Negiah, section entitled "Shaking Hands in Halacha," for a discussion regarding Rav Moshe's opinion on this topic, both with regard to initiating a handshake and with regard to returning a handshake (i. e., where the other party extends his/her hand first). For a translation of R' Moshe's three Teshuvos (responsa) on men shaking hands with women, see [1]
^E. g., see Sinclair, Daniel. Jewish Biomedical Law 2004
^See RCA decision and, earlier, RCA Roundtable. (Statement by Saul Berman, Reuven Bulka, Daniel Landes and Jeffrey Woolf.) "Proposal on smoking" (unpublished) July 1991.
