Reference for Niddah 50:13

תנא אם היתה נקבה נדונה כשעורה סדוקה

give no practical decision [on the validity of a birth] unless the embryo has hair [on its head]. But could Samuel have said such a thing, seeing that he ruled, 'In either case must she consider the possibility of a valid birth'? — R. Ammi b. Samuel replied: This was explained to me by the Master Samuel: She must indeed take into consideration the possibility of a valid birth;<span class="x" onmousemove="('comment',' Sc. to remain unclean for fourteen days. ');">¹¹</span>

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