Yosef Samberg asked:
According to the Gemara, items must be formed with the body and must grow back in order to transmit tumah.Therefore, teeth, nails, and hair that do not have both conditions do not transmit tumah. Accordingly, skin should also not transmit tumah. Why is skin not listed?
Yosef Samberg, silver spring, MD, USA
The Kollel replies:
Your question is actually asked by the Gemara in Nidah (55a). The Gemara's first answer is that skin is not Tamei mid'Oraisa, and is only Tamei mid'Rabanan due to a Gezeirah. The Gemara's second answer is that in fact skin is not considered to grow back (on par with nails and skin, see Gemara at length).
All the best,
Yaakov Montrose