רָחֵל שֶׁלֹּא בִּכְּרָה וְיָלְדָה שְׁנֵי זְכָרִים. אֲפִלּוּ יָצְאוּ שְׁנֵי רָאשֵׁיהֶן כְּאֶחָד אִי אֶפְשָׁר שֶׁלֹּא קָדַם אֶחָד. הוֹאִיל וְאֵין יָדוּעַ אֵי זֶה מֵהֶם יָצָא רִאשׁוֹן הַכֹּהֵן נוֹטֵל אֶת הַכָּחוּשׁ וְהַשֵּׁנִי סְפֵק בְּכוֹר. מֵת אֶחָד מֵהֶן אֵין לַכֹּהֵן כְּלוּם שֶׁזֶּה הַחַי סָפֵק הוּא וְהַמּוֹצִיא מֵחֲבֵרוֹ עָלָיו הָרְאָיָה. וְכֵן אִם יָלְדָה זָכָר וּנְקֵבָה הֲרֵי הַזָּכָר סָפֵק שֶׁמָּא הַנְּקֵבָה יָצָאת תְּחִלָּה לְפִיכָךְ אֵין לַכֹּהֵן כְּלוּם שֶׁהַמּוֹצִיא מֵחֲבֵרוֹ עָלָיו הָרְאָיָה:
The following laws apply when a sheep that had not given birth before gives birth to two males. Even if both of their heads emerged at the same time, it is impossible that one did not emerge before the other. Since it is not known which emerged first, the priest should take the weaker one and the second one is a firstborn of doubtful status. If one of them died, the priest does not receive anything, for the living offspring is of doubtful status and we follow the principle: "When one desires to expropriate property from a colleague, the burden of proof is on him." Similarly, if the mother gave birth to a male and a female, the male is of doubtful status, for perhaps the female emerged first. Therefore the priest does not receive anything, for when one desires to expropriate property from a colleague, the burden of proof is on him.
