We are learning the second Mishnah in the ninth chapter of Tractate Bava Basra. The subject of the Mishnah revolves around the tumtum. The meaning of the word 'tumtum' is covered or blocked, and it refers to a person born with their private parts covered by a sort of membrane, in a way that makes it impossible to determine whether they are male or female.
Two opinions on the status of a tumtum:
The opinion of the Sages - They are the Tanna Kamma in our Mishnah, and the halachah follows their opinion. According to them, the tumtum is a case of doubt whether male or female, and we do not know to which one they belong. Since in our Mishnah boys and girls will dispute over rights in the estate, the rule "ein safek motzi midei vadai" - a doubt cannot extract from a certainty - will apply. A situation of doubt cannot extract money from a situation of certainty. And similarly the rule "hamotzi meichaveiro alav hara'ayah" - the burden of proof is on the one who seeks to extract from their fellow: the tumtum cannot extract money or economic rights, since he is defined as a doubt, perhaps a son and perhaps a daughter.
The opinion of Rabban Shimon ben Gamliel - This opinion is reflected in the second part of the Mishnah, although there is no explicit mention of it, since this part represents the words of a different Tanna. According to his opinion, the tumtum is neither male nor female, but rather a completely separate category, a gender in its own right. There is no doubt here, but a certainty: neither male nor female. The halachah does not follow this opinion, but we will see how these things are brought in the continuation of the Mishnah.
"Hiniyach banim uvanos vetumtum" - He left sons and daughters and a tumtum:
A person passes away and leaves behind five children: two sons, two daughters, and the tumtum. How do we divide the estate? It is established that the tumtum loses out from both directions. On the one hand, the sons have the advantage that they are the heirs and they exclude the daughters from the inheritance. On the other hand, the daughters have an advantage that we just learned about in the previous Mishnah: if there is not enough money for everyone, the estate is held first and foremost to support the daughters until they reach the age of maturity, twelve and a half, or until they marry, and only afterward does the rest of the estate pass to the sons as an inheritance.
"Bizman shenechasim merubin" - When there is an abundance of assets to divide, "hazecharyim dochin oso eitzel hanekevos" - the males push him to the females. The sons say to him: Perhaps you are a daughter, and we do not know, and therefore you are with the daughters. That is to say, you can receive support until the age of twelve and a half, but you are not among the heirs. In such a case, the estate will be divided in two between the two sons alone, and not into three or five parts.
"Nechasim muatin" - When there is not enough to divide among everyone, for example, one apartment from which the five children are supposed to be supported, and they move to live with their uncle and the Beis Din takes the apartment to rent it out. From the money received, "hanekevos dochos oso eitzel hazecharim" - the females push him to the males: the daughters, or the guardian acting on their behalf, will claim in Beis Din that perhaps he is a son, and therefore he has no right to collect from the rental money designated to support the daughters until they marry or reach maturity. It turns out that the tumtum will be forced, like his brothers, to beg at people's doors.
It is worth adding that if there is enough money to support both the daughters and the tumtum, he will certainly also receive support until the age of twelve and a half, since it does not come at the expense of the daughters. His situation is not worse than that.
A shechiv mera's gift to a fetus:
The next part of the Mishnah also deals with the tumtum, and adds a new principle. We learned in the previous chapter about the concept of a 'shechiv mera', a person who is near death. There is a Rabbinic enactment according to which we are concerned that if the shechiv mera becomes distressed or worried that he did not arrange his financial affairs, the distress and pressure will lead to his premature passing, Heaven forbid. Therefore, the Sages established that the declaration of a shechiv mera regarding the distribution of his assets is binding, as if he made an actual formal kinyan.
Here the Mishnah wishes to introduce an additional novel concept. Usually, any kinyan requires two parties, and if one of the parties is not alive, there is no second party, and therefore there is no way to transfer ownership to someone who has not yet been born. Nevertheless, our Mishnah says that a shechiv mera can give a gift through speech for the benefit of his fetus, and his gift is binding. This is the novel teaching of the Mishnah: this too is included in the Rabbinic enactment, since a person has a special closeness in his heart to his fetus, and if he cannot care for it as he wishes he will suffer great distress, and this will lead to consequences that we do not want.
And so the Mishnah says: "Ha'omer im teiled ishti zachar yitol maneh" - A person on his deathbed says that if his pregnant wife gives birth to a son, the son will receive a maneh, which is one hundred zuz. "Yaldah zachar notel maneh" - If a son is born, he receives the one hundred zuz as was stated, because the Rabbis established it so. And similarly if he said "nekevah masayim" - that if his wife gives birth to a daughter she will receive two hundred zuz, then "yaldah nekevah noteles masayim" - the daughter receives the two hundred zuz, for that exact same reason.
The Mishnah specifically chose these examples to show that it is the way of the world and a normal thing for a person to give his daughter more than his son: with a daughter, they wish to prevent a situation where she reaches poverty and is forced to beg at people's doors out of desperation, and therefore it is natural to ensure that she is cared for even more than what the son receives.
"Veyaldah zachar unekevah" - and she gave birth to a male and a female:
The deathly ill person said, "Im zachar maneh, im nekevah masayim" - if a male, a maneh; if a female, two hundred, and it turns out she gave birth to fraternal twins, a boy and a girl. The Mishnah says: "Zachar notel maneh, unekevah noteles masayim" - a male takes a maneh, and a female takes two hundred. Seemingly, there is no great novelty here, certainly in light of what was said in the previous lines. However, the novelty is that even though he used the grammatical phrasing of "if a male... if a female," phrasing that hints at only one child, and he did not expect two at all - one might mistakenly think that in the case of twins, they would not both receive. This is not so. His intention is understood: the boy, whether there is one or two, will receive a maneh, and the girl, whether one or two, will receive two hundred.
"Yaldah tumtum eino notel" - if she gave birth to a tumtum, he takes nothing:
He said that the boys take a maneh and the girls two hundred, and a tumtum was born - he takes nothing. This is again the view of Rabban Shimon ben Gamliel, which does not align with the first part of the Mishnah. According to the first part, which is the view of the Sages and the halachah, the tumtum is a doubt whether he is a boy or a girl. Since we do not know if he deserves a maneh or two hundred, we know at the very least that he deserves a maneh, because "mima nafshach" - whichever way we look at it, a hundred zuz is coming to him, and therefore the tumtum will take a maneh.
However, Rabban Shimon ben Gamliel, who is speaking in this part of the Mishnah, maintains that a tumtum is a distinct gender, a completely different category, and is neither a boy nor a girl. The giver did not refer at all to a case of someone who is neither a boy nor a girl, and therefore the tumtum is not entitled to a maneh or to two hundred, and takes nothing. The halachah does not follow his view.
"Im amar kol mah sheteled ishti yitol" - if he said, whatever my wife gives birth to shall take:
If the husband said that whatever his wife gives birth to shall take, whether a maneh or two hundred or any gift he states, then if she gave birth to a tumtum - the tumtum takes the gift. The novelty is that one might mistakenly think that this is not his desire and he did not intend for a tumtum, and who would even think about a tumtum. Nevertheless, the tumtum is included in his words.
"Im ein sham yoresh ela hu - yoresh es hakol" - if there is no heir but him, he inherits everything:
Even according to the view of Rabban Shimon ben Gamliel, if there is no other heir besides the tumtum, he inherits everything. That is, when the tumtum has no brothers or sisters, he takes the entire estate. Seemingly, we must wonder: who else would inherit, for is he not his child? But the verse dealing with inheritance speaks of a case of a son or a daughter, and a tumtum, in the opinion of Rabban Shimon ben Gamliel, is neither this nor that. The answer is that nevertheless, he inherits, for the verse continues and says, "his relative that is next to him of his family, and he shall possess it" - the closest relative in the family is the heir. Therefore, even though he is neither a son nor a daughter, he is still the closest relative, being the child and offspring of the deceased, and the tumtum will inherit everything.
And this is the law even if it is not his child: for example, a person who has no children and has a single sibling who is a tumtum - since he has no children, his tumtum sibling is the heir, even according to Rabban Shimon ben Gamliel.
In summary: The halachah is ruled according to the view of the Tanna Kamma, who are the Sages, that a tumtum is a status of doubt and cannot inherit before the sons, and is found, as it were, losing on both sides - but he is not a gender unto himself.