Rambam codifies the mitzvah of procreation and related marital obligations, providing a foundational halakhic framework for issues of conception and family continuity.
לֹא יִשָּׂא אָדָם עֲקָרָה וּזְקֵנָה וְאַיְלוֹנִית וּקְטַנָּה שֶׁאֵינָהּ רְאוּיָה לֵילֵד אֶלָּא אִם כֵּן קִיֵּם מִצְוַת פְּרִיָּה וּרְבִיָּה אוֹ שֶׁהָיְתָה לוֹ אִשָּׁה אַחֶרֶת לִפְרוֹת וְלִרְבּוֹת מִמֶּנָּה. נָשָׂא אִשָּׁה וְשָׁהֲתָה עִמּוֹ עֶשֶׂר שָׁנִים וְלֹא יָלְדָה הֲרֵי זֶה יוֹצִיא וְיִתֵּן כְּתֻבָּה אוֹ יִשָּׂא אִשָּׁה הָרְאוּיָה לֵילֵד. וְאִם לֹא רָצָה לְהוֹצִיא כּוֹפִין אוֹתוֹ וּמַכִּין אוֹתוֹ בְּשׁוֹט עַד שֶׁיּוֹצִיא. וְאִם אָמַר אֵינִי בּוֹעֲלָהּ וַהֲרֵינִי שׁוֹכֵן עִמָּהּ בִּפְנֵי עֵדִים כְּדֵי שֶׁלֹּא אֶתְיַחֵד עִמָּהּ בֵּין שֶׁאָמְרָה הִיא בֵּין שֶׁאָמַר הוּא אֵין שׁוֹמְעִין אֶלָּא יוֹצִיא אוֹ יִשָּׂא אִשָּׁה הָרְאוּיָה לֵילֵד: שָׁהֲתָה עֶשֶׂר שָׁנִים וְלֹא יָלְדָה וַהֲרֵי הוּא יוֹרֶה כְּחֵץ שִׁכְבַת זֶרַע. חֶזְקַת הַחלִי מִמֶּנָּה וְתֵצֵא שֶׁלֹּא בִּכְתֻבָּה וְיֵשׁ לָהּ תּוֹסֶפֶת. לֹא תִּהְיֶה זוֹ פְּחוּתָה מֵאַיְלוֹנִית שֶׁלֹּא הִכִּיר בָּהּ שֶׁיֵּשׁ לָהּ תּוֹסֶפֶת כְּמוֹ שֶׁיִּתְבָּאֵר. וְאִם אֵינוֹ יוֹרֶה כְּחֵץ חֶזְקַת הַחלִי מִמֶּנּוּ בִּלְבַד וְיוֹצִיא וְיִתֵּן הַכְּתֻבָּה כֻּלָּהּ עִקָּר וְתוֹסֶפֶת:
A man should not marry a barren women, an elderly woman, an aylonit or a minor who is not fit to bear a child unless he has already fulfilled the mitzvah of being fruitful and multiplying, or he has another wife with whom he can father children. When a man has married a woman and remained married to her for ten years without her bearing children, he must divorce her and pay her [the money due her by virtue of her] ketubah, or marry a woman who is fit to bear children. If he does not desire to divorce her, he should be compelled to do so; he should be beaten with a rod until he divorces her. Even when he says, "I will not engage in marital relations with her. Instead, we will dwell together with witnesses so that we will not ever be in private," regardless of whether it is he or she who offers this proposition, it is not accepted. Rather, he is required to divorce [his wife] or marry another woman who is fit to bear children. When a man has lived [together with his wife] for ten years without her bearing children, and he releases semen as one shoots an arrow, it can be assumed that the affliction comes from her. Therefore, he should divorce her without paying her [the essential requirement of] the ketubah. She is, however, entitled to the additional sum [by which the ketubah was increased]. [The rationale is that] such a woman should not be judged more severely than an aylonit whose husband did not recognize her condition, who is granted the additional amount, as will be explained. If [the husband] does not [release semen] as one shoots an arrow, it can be assumed that the affliction comes from him alone. When he divorces her, he must pay her [the entire sum due her by virtue of her] ketubah: the essential requirement and the additional sum.
