כִּֽי־תִהְיֶ֨יןָ לְאִ֜ישׁ שְׁתֵּ֣י נָשִׁ֗ים הָאַחַ֤ת אֲהוּבָה֙ וְהָאַחַ֣ת שְׂנוּאָ֔ה וְיָֽלְדוּ־ל֣וֹ בָנִ֔ים הָאֲהוּבָ֖ה וְהַשְּׂנוּאָ֑ה וְהָיָ֛ה הַבֵּ֥ן הַבְּכ֖וֹר לַשְּׂנִיאָֽה׃
Cuando un hombre tuviere dos mujeres, la una amada y la otra aborrecida, y la amada y la aborrecida le parieren hijos, y el hijo primogénito fuere de la aborrecida;
Mishnah Bekhorot
A fetus extracted by means of a caesarean section and one that follows neither is a first-born for inheritance or a first-born to be redeemed from a priest. Rabbi Shimon says: the first is a first-born for inheritance and the second is a first-born as regards [the redemption] with five selas.