1. Question: Why are there some poskim who hold that if one isn’t sure whether he fulfilled the mitzvah of Omer or not he should still say a blessing and count the Omer for that night but they would also hold that a tumtum should not say a blessing upon putting on tzitzis?
A. A tumtum is a person born without clear signs of genitalia, it might be the person has to much fat or skin in the area to make a judgment whether it is female or male therefore there is a halachic doubt whether it is obligated in the mitzvah of tzitzis, so he should wear the tzitzis in doubt but should not say a blessing because, safek brachos lihakel, we are lenient to not say a blessing when in doubt lest we might say Hashem’s name in vain.
B. Shouldn’t this opinion, also be concerned that the person might have said the Omer already and saying a blessing potentially again might constitute saying Hashem’s name in vain so when in doubt don’t make the blessing?
Answer: This opinion holds that when there is a doubt of whether there is a mitzvah to begin with then one should not say a blessing but by this case of the Omer there was a definite obligation the only question is whether it was fulfilled yet or not therefore he holds a blessing should still be said since a definite obligation exists.(See Dirshu Mishna Berura footnote 41 on Be’ur Halacha 489:1 “moneh viholech”)
If you are in doubt whether you said Shema or blew shofar or shook lulav on the
first day of the respective Yom Tov, you should perform those mitzvos with
their blessing according to some opinions, (See Mishna Berura 67:1:1), which
means by Shema the blessings before and after should be said. Why then if a
person was only able to hear shofar or shake lulav at bein hashmashos,
twilight, or whether a tumtum wears tzitzis or an androgynous gets a bris, in
those cases no blessing is made because when in doubt be lenient and don’t say
a blessing in doubt?
Background: A. A tumtum is a person who does not have seeable genitalia because it is covered up by extra flesh so there is a doubt of whether the person is male or female. Women aren’t obligated in tzitzis. B. An androgynous is a person with both genitalia which there is also a doubt what gender it is or maybe even a third type of person. Women certainly don’t get a bris. C. Bein hashmashos, or twilight is a time when there is a question whether it is halachically day or night. One cannot fulfill the mitzvos of shofar or lulav at night.
Answer: In cases where we would say a blessing are scenarios where the person is obligated in the mitzvah but is just in doubt whether he did it or not therefore since there is a definite obligation he just isn’t sure whether he fulfilled it or not there is an original assumption that he did not do it yet and still is obligated. A mitzvah fulfilled in doubt does not remove a definite obligation one has. Whereas when a blessing should not be said are in cases where there is a doubt if there is even an obligation at all. (However there is an opinion that by any doubt one should not say a blessing when fulfilling the mitzvah, (See Mishna Berura here in its totality and Dirshu footnote 1.)