Gemara

(Shmuel): We write a document of rebellion against an Arusah, but not against a Shomeres Yavam.

Question (Beraisa): We write even for an Arusah or a Shomeres Yavam.

Suggestion: Perhaps Shmuel discusses when he rebels. He teaches that we write for an Arusah, but not for a Shomeres Yavam!

Objection: Presumably, we don't write for a Yevamah because she is not commanded to have children. The same applies to an Arusah!

We must say that we write for an Arusah who wants children to support her in her old age and to bury her when she dies. A Yevamah can also claim this!

Yevamos 64a (Beraisa): If a man married a woman and she did not give birth in 10 years, he must divorce her and pay a Kesuvah. Perhaps (she is not sterile, just) he did not merit to have children through her.

Question: Why do we say that he pays a Kesuvah because he did not merit to have children through her? Perhaps she did not merit to conceive from him!

Answer: Since she is not commanded about Peru u'Rvu, she would not be punished by inability to fulfill it.

65a (R. Ami): If each of them says that the other is sterile, this is 'matters between the two of them'. She is believed (and receives a Kesuvah), for she can tell whether or not he is Yoreh k'Chetz (his semen shoots out at the time of Bi'ah), but he cannot.

65b (Mishnah): A man is commanded "Peru u'Rvu", but a woman is not;

R. Yochanan ben Brokah says "Peru u'Rvu" was said to both Adam and Chavah.

R. Yochanan and R. Yehoshua ben Levi argued about whether the Halachah follows R. Yochanan ben Brokah or Chachamim. An Amora said that R. Yochanan rules like R. Yochanan ben Brokah; R. Ami and R. Asi turned their faces. We infer that (they were sure that) R. Yochanan rules like Chachamim.

A childless couple came before R. Yochanan. He obligated the husband to divorce her and pay a Kesuvah.

Inference: She is commanded. If not, he would not need to pay a Kesuvah!

Rejection: Perhaps she had a claim (why she needed children);

A woman (to R. Ami): Force my husband to (divorce me and) pay my Kesuvah (we are childless).

R. Ami: No, you are not commanded to have children!

The woman: What will be in my old age (if I have no children)?

R. Ami: If this is her concern, we certainly force him.

A woman came before Rav Nachman with a similar request. He acceded when he heard that she desires a son for her old age and to bury her.

Nedarim 90b (Mishnah): At first, if a woman said to her husband 'let Shomayim judge between me and you', Beis Din would force him to divorce her and pay her Kesuvah. Chachamim changed this, lest women use this claim in order to marry someone else. Rather, he tries to appease her.

Rishonim

Rif and Rosh (6:20): The Halachah does not follow R. Yochanan ben Brokah. If a woman desires a son to support her in her old age and to bury her, we force her husband to divorce her and pay a Kesuvah.

Rosh: We discuss when she did not have children in 10 years and we know that he is sterile, so we are not concerned lest she desires another man

Rif: Some say that she receives Ikar Kesuvah of 100 or 200, but not Tosefes. Even though Tanai Kesuvah are like the Kesuvah, he intended to add to her Kesuvah only if she would remain with him. Mema'enes and other cases (i.e. a Shniyah or Ailonis) have Tosefes but not Ikar Kesuvah; this was explicitly taught. He realized that she can leave him if she wants (or that he must divorce her), and freely gave away his money. Just like some receive Tosefes Kesuvah but not Ikar , some receive Ikar but not Tosefes . One who says that here she receives Ikar and Tosefes must bring a proof.

Rosh: R. Chananel proves this from Kesuvos 54b. Tanai Kesuvah are like the Kesuvah for one who sells or pardons it. It does not say that they are the same for one who leaves because she needs children. We find that Tanai Kesuvah are unlike the Kesuvah regarding Mema'enes and others. R. Tam says that Tanai Kesuvah are always like the Kesuvah. Mema'enes and others do not receive (Ikar) Kesuvah because retroactively they were never married. The Tosefes was a gift. Here we follow R. Chananel and the Rif; he pays only Ikar Kesuvah.

Rambam (Hilchos Ishus 15:10): If after 10 years a woman demands to be divorced because she did not have children and she says that Eino Yoreh k'Chetz, we heed her. Even though she is not commanded about Peru u'Rvu, she needs children for her old age. We force him to divorce her and pay only Ikar Kesuvah. He did not write Tosefes Kesuvah with intent that she will decide to leave him and receive it.

Rebuttal (Ra'avad): She has a Kesuvah from her first two husbands even if she says nothing about his Bi'ah.

Magid Mishneh: This law cannot apply to before 10 years, for she is no better than he. He is commanded about Peru u'Rvu, yet he need not divorce until 10 years! Also, we have no source for any Shi'ur of time less than 10 years.

Question (Lechem Mishneh): If she is no better than he, why did Mishnah Rishonah force him to divorce her and pay a Kesuvah? Also, the Magid Mishneh should have brought a better proof that R. Ami's law is after 10 years. We must say so, and that the Mishnah (Nedarim 90b) is within 10 years. We cannot say that both discuss before or after 10 and the Mishnah is when she does not demand children, for then the Mishnah Rishonah would not force him to divorce her.

Lechem Mishneh: Tosfos (Yevamos Reish 64a) asked why the case of a woman who demands to be divorced because she needs children was not listed among cases when we force a man to divorce (Kesuvos 77a). We cannot say (like we answered why it omits one who did not have children in 10 years) that we teach only cases when we force only if she wants to leave. Here also we must discuss a man who already fulfilled Peru u'Rvu, for otherwise she would not need a claim! Rather, there we taught only cases when she receives the entire Kesuvah.

Question (Rosh 15): If R. Ami's law (she is believed to say that Eino Yoreh k'Chetz) applies after 10 years, even without her claim he would need to divorce her and pay a Kesuvah, for he did not merit to have children through her. If his law is before 10 years, we should be concerned lest she desires another man, like the Mishnah Acharonah!

Suggestion: R. Ami discusses when she claims that she needs children for her old age, and the Mishnah is when she does not claim this.

Rejection (Rosh): In any case, R. Ami should be concerned lest she desires another man. Also, if in the Mishnah she does not demand children, the Mishnah Rishonah would not require him to divorce her and pay a Kesuvah! Our Sugya requires him to divorce her and pay a Kesuvah (even though she is not commanded about Peru u'Rvu) when she makes this claim. We can say that this is when we know that he is sterile, or like BaHaG says, when they were together 10 years and he had children from another wife. We cannot give this answer here, for it would apply even if he is Yoreh k'Chetz!

Poskim

Shulchan Aruch (EH 154:6): If a woman says that she wants a child to support her in her old age (Rema - and she has no children) and her husband is Eino Yoreh k'Chetz, we force him to divorce her.

Beis Shmuel (10): The Nimukei Yosef (21a DH Masnisin) says that even if she has a daughter, we do not force him.

Shulchan Aruch (ibid.): This is if she was with him for 10 years without pregnancy and does not demand a Kesuvah, so we will not suspect that she seeks a Get in order to collect her Kesuvah, and we have no source to suspect that she seeks a Get for another reason.

Source (Gra 24,25): The Ritzva (in Tosfos 65b DH Ki) did not believe a woman because she requested a Kesuvah. This is like 117a (if a woman says that her husband died and she requests her Kesuvah, she is not believed). We learn from there to other motives for a Get. The Mishnah Acharonah suspects that a woman desires another man. In our case we are not concerned unless something arouses suspicion.

Shulchan Aruch (ibid.): Even if he has children from another wife, perhaps he worsened afterwards. He pays 100 or 200, but not Tosefes. In any case if we know that he is sterile he must divorce her immediately.

Beis Shmuel (16): This is like Tosfos. The Rosh (20) holds that within 10 years even if we know that he is sterile we are concerned lest she desires another man

Rema: The same applies if she did not have a child from him in 10 years and demands children. She must claim Eino Yoreh k'Chetz only when he already had children, or if this is the third time she was married without children, for then we would have assumed that (only) she is sterile.

Gra (37): Others say that if she was married three times without children she is not believed to make him pay a Kesuvah.