Reference for Yevamot 200:13
ואלא בגרושה ומאי אחר בעלה אחר גט בעלה אימא סיפא הוא אין מטמא להם והם אינן מטמאין לו בשלמא הן אין מטמאין לו לחומרא דכל חד וחד דלמא לאו בריה הוא אלא הוא אין מטמא להם אמאי
he is silenced [if he claims any] of the rights of priesthood.<span class="x" onmousemove="('comment',' He is not allowed to take part in the Temple service though eligible to marry a woman of pure stock. ');"><sup>38</sup></span> What is the reason? — Scripture stated, And it shall be unto him, and to his seed after him,<span class="x" onmousemove="('comment',' Num. XXV, 13, speaking of the priesthood. ');"><sup>39</sup></span> it is, therefore, required that 'his seed' shall be traced to 'him',<span class="x" onmousemove="('comment',' Only such a priest can transmit the rights of priesthood to his seed. ');"><sup>40</sup></span> but this is not the case here.<span class="x" onmousemove="('comment',' Lit., 'and it is not'. Since the father of the shethuki is unknown he cannot transmit the rights of priesthood to him. ');"><sup>41</sup></span>