The sacred texts of Judaism and Islam are in absolute agreement when it comes to the pig: It is taboo, unclean and unfit for human consumption.

For Jews, pork is “treyf,” the very opposite of kosher. Pigs have one of the characteristics needed to be kosher (split hooves) but lack the other (they don’t chew their cud).

For Muslims, the pig is also forbidden, or “haram,” along with carrion and blood. The Quran mentions the proscription repeatedly.

Now biotech companies are raising genetically altered pigs to transplant their organs into patients whose own kidneys have failed. Experts in the field are only beginning to grapple with the question: Will Jews and Muslims accept a transplanted organ from a pig if it saves their lives?

It has not always been entirely clear whether the religious prohibitions on pigs apply strictly to consumption, and neither of these religions has a supreme authority, like the pope, who would issue a decree applicable to all.

Questions of religious acceptance of cross-species transplants came up at the Congress of the Transplantation Society in Istanbul, where scholars from a variety of faiths met last year.