(Beraisa): (An Olah must be a) "Zachar", and not a female.

Another verse requires Olah to be "Zachar". It excludes Tumtum and Androginus.

This is unlike the first Tana of our Mishnah. He is unsure about the gender of Androginus. A verse would not teach about such a Safek!

58a (Beraisa - Ben Azai): Because Tana'im argue about whether Rosh Hashanah for Ma'aser Behemah is the first of Elul or Tishrei, animals born in Elul are tithed by themselves.

(Rava): According to Ben Azai, if five were born in Av, five in Elul and five in Tishrei, he brings them into the pen for Ma'aser; he takes an Eluli for Ma'aser, and the others are exempt in any case;

If Rosh Hashanah is Elul 1, those of Elul and Tishrei joined, and there were only five from the year before. If Rosh Hashanah is Tishrei 1, those of Elul and Av joined, and there are only five from the coming year.

Suggestion: In the latter case, those of Tishrei should join animals that will be born before the next Goren!

Rejection: The Torah requires a definite Asiri, and not a Safek! (Since perhaps those of Tishrei were properly tithed, they are exempt from Ma'aser.)

Rishonim

Rif and Rosh (Hilchos Tum'ah (after Menachos) 1b and 6): "Lah Yitamei" teaches that one is Metamei for a Vadai (relative), but not for a Safek.

Rosh (ibid.): E.g. Therefore, if babies became mixed together, or we are unsure if Leah's baby was born after nine months from her first husband, or after seven months from her latter husband, or a woman was Safek divorced, he is not Metamei for either Safek father. When we are unsure from which father the baby was, if both possible fathers are Kohanim, they are not Metamei for the child, and he is not Metamei for them.

Rambam (Hilchos Evel 2:3): "Lah Yitamei" teaches that one is Metamei for a Vadai (relative), but not for a Safek. Therefore, if babies became mixed together, or we are unsure if Leah's baby was born after nine months from her first husband, or after seven months from her latter husband, and all similar cases, he is not Metamei for either Safek father. Similarly, if a woman was Safek divorced or received a Pasul Get, her (ex)husband is not Metamei for her.

Kesef Mishneh: This is from Toras Kohanim.

Oneg Yom Tov (71 DH v'Kivan): We do not follow the majority regarding a Safek Mamzer. This is why the Rambam says that Safek Kidushin or Safek Kidushin produces a Safek Mamzer, and we do not follow the Chazakah, since a majority is stronger than a Chazakah. However, everywhere we follow the majority mid'Oraisa, and we forbid only mid'Rabanan, e.g. Yevamos 31a. The Rashba (Kidushin 66a DH v'Eino) says that when he threw Kidushin to her and it is a Safek to whom it was closer, we leave her in her Chazakah (she is single). When he threw a Get to her and it is a Safek to whom it was closer, we leave her in her Chazakah. According to Torah law, she may do Yibum (if her husband died without children). If he is a Kohen, she is permitted to him. The Rambam cited a Beraisa that the Rosh brings. Why can't one be Metamei after Safek divorce? We should rely on the Chazakah!

Suggestion: It is only mid'Rabanan that he is not Metamei for her. Even though the Halachah follows R. Akiva, that it is a Torah Chiyuv to be Metamei for her, Chachamim can uproot this through telling people to be passive. We are concerned lest she really was divorced.

Rejection (Oneg Yom Tov): The Rambam connotes that he learns from "Lah Yitama". This is like the case of babies who became mixed; the Torah forbids them to be Metamei. The same applies to one who received a Pasul Get. Pasul means that mid'Oraisa it is Kosher, and mid'Rabanan it is Pasul. Therefore, mid'Oraisa he may not become Tamei for her. Why don't we leave her in her Chazakah (for cases of Safek)? I answer that since the Torah taught that one is Metamei only for Vadai, and not for Safek, this shows that it is called a Safek in spite of the Chazakah, like we said about a Safek Mamzer.

Rosh (Yevamos 1:4): A Vadai Sotah (she was definitely Mezanah) is exempt from Yibum and Chalitzah (if her husband died without children). A Safek Sotah must do Chalitzah, like the Mishnah (Sotah 2a) says. Even though 'Tum'ah' is written regarding a Safek Sotah, just like regarding a Vadai, we concluded that that verse really discusses a Vadai Sotah. We expound that once she was secluded, she is forbidden to her husband, the Bo'el, and Terumah. The Torah forbids a Safek like a Vadai. This is only to be stringent, therefore she needs Chalitzah. If so, why did the Gemara (Sotah 5b) suggest that she should do Yibum? Even though we forbid her due to Safek Tum'ah, she is not considered even Safek Ervah.

Avnei Nezer (EH 18:2): Tosfos and the Rosh say that Chachamim made a Safek Sotah like a Vadai only to be stringent. R. Yo'av Yehoshua explains that when the Torah excluded a Safek to teach that we may be lenient, then it is Vadai Heter (regardless of what really occurred). When the Torah excluded a Safek to teach that we must be stringent, since if this will result in a leniency, we will not consider it to be Vadai, also to be stringent it is not considered Vadai. If a Kohen divorced his wife, and she remarried and gave birth seven months later, we expound that the child may not become Tamei for either Safek father. We should say that in any case he may become Tamei for the first, for if he is from the latter, he is a Chalal (not a Kohen)! According to R. Yo'av, we can say that since the Torah taught that we must be stringent, we do not say 'either way it is permitted.'

Rambam (Hilchos Bechoros 6:16): If an animal exempt from Ma'aser, e.g. it was bought or orphaned, became mixed with the flock, all are exempt, because each of them is a Safek.

Avnei Nezer: The Shitah Mekubetzes (Bava Metzi'a 6b DH Kafatz) exempts a Safek 10th (from Ma'aser) even when a majority opposes this. A support for this is the Shev Shemaitsa, Beis Meir and the Mishnah that permit a Shtuki (Safek Mamzer) to marry a Mamzer (since the Torah permitted a Safek Mamzer, even though most Shtukim are Kesherim).

R. Akiva Eiger (2:65): The Yerushalmi says that the Isur of Machazir Gerushaso takes effect in addition to the Isur of a Sotah. Do not say that here there is a Gezeras ha'Kasuv that Isur Chal Al Isur. We can say that the verse forbids even if later the witnesses were Huzam, so retroactively, she was never forbidden due to Sotah. The questioner said that the Isur takes effect on her, for she was never forbidden to her husband, since she says that she was not defiled. Only her husband, who was unsure, was forbidden. Since the Isur takes effect on her, it takes effect on her husband. I disagree. The Beis Shmuel (11:2) and Mishneh l'Melech (Hilchos Sotah 2:12): say that warning and seclusion forbid (also) her until she drinks. The Chelkas Mechokek disagrees in a case that she wants to drink and her husband does not want to, but he agrees about an Arusah (who cannot drink), even if she says that she is innocent. And even if we would say that there is no Isur on her, since Beis Din is unsure, they cannot lash her husband for Machazir Gerushaso, for if she really sinned the Isur did not take effect. I wanted to say that Beis Din lashes him mi'Mah Nafshach (in any case), for Sotah if she really sinned, or for Machazir Gerushaso if she did not. Tosfos (Zevachim 78a DH ha'Pigul) says that this is not Safek warning. However, this is wrong. The Torah forbids a Safek Sotah as if she was Vadai, as long as we are unsure. Even if she did not sin, there is a Vadai Isur Aseh of Sotah, so Machazir Gerushaso does not take effect. If her husband swore to forbid her to him, and later she drank and was found to be innocent, since she was Vadai forbidden at the time, his oath did not take effect. Had the Torah forbade her only due to Safek, the oath would have taken effect, like the Shach (YD 238:25) says.

Tosfos (Yoma 74a DH Itztrich): We expound verses to teach about Safek Ma'aser Behemah (Bechoros 58b) and a Safek whether or not a Nega (Tzara'as) preceded the white hair, and did not ask! A Kvi is different, for it is always the same. If the Torah came to teach about it, it should teach what it is!

Maharit (YD 2:1 DH v'Iy): Tosfos answered that this Safek is different, for it is always the same. He did not distinguish Sefekos in which we would need to be stringent without a verse. He must agree that mid'Oraisa, all Sefekos are permitted, like the Rambam.

Divrei Malki'el (3:89): Just like a verse cannot teach about a Safek (to us) that (Hash-m knows that it) is always the same, it cannot teach about a Safek that we have about the Halachah. If so, why does a verse teach about Ma'aser Behemah? Hash-m knows whether Rosh Hashanah for Ma'aser Behemah is the first of Elul or of Tishrei! It seems that Tosfos said so only regarding a Koy. Since it is always a Behemah or always a Chayah, we cannot say that the Torah excluded it due to Safek. If the Torah was concerned lest we be unsure about it, it should have taught us the law! Regarding Safek Asiri and Safek Mamzer, the Torah needed to teach about all Sefekos (e.g. was the animal already counted), and automatically a Safek about the Halachah is included. R. Akiva Eiger holds that since the Torah would not teach that something is a Safek (if it is always the same), we cannot use an exclusion to exclude also such a Safek.