The Chasam Sofer's Quip at a Pidyon HaBen

Now back to our story with the Chasam Sofer. A family was celebrating the mitzvah of pidyon ha’ben. The lavish seudah was over and it was time to bentch. The ba’al simcha honored one of the guests to lead the zimun. After the zimun leader finished bentching, one of the other guests asked him, “Why didn’t you start bentching with ‘B’reshus ha’kohanim’?” (It is respectful for a non-kohen who is leading the bentching to humbly announce that he is leading the bentching with the consent of the kohanim present.)

The zimun leader answered, “How was I supposed to know there was a kohen here?” The guest retorted, “We’re at a pidyon ha’ben! Of course there’s a kohen here.” The zimun leader did not have an answer.

At this point the Chasam Sofer said as follows. Maybe the husband of a bas kohen performed the pidyon ha’ben. The Gemara in Kiddushin states that Rav Kahane accepted an item of value in the performance of pidyon ha’ben. How is that possible? Rav Kahane was not a kohen! Tosfos suggest that he may have been using the same method mentioned in the Gemara in Chullin. He accepted the redemption on behalf of his wife. So perhaps there is no male kohen here who can lead the bentching, but only a Yisrael who is married to a bas kohen who accepted the pidyon on behalf of his wife.