If they were to genetically modify a pig to chew its cud, would it be kosher?

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    I think it would be a lot simpler to create split hooves... – yydl Aug 27 '10 at 0:55
  • On a camel, hyrax, or hare, you mean ... – Shalom Aug 27 '10 at 1:26
  • ... or any other non-split cud chewer. – Isaac Moses Aug 27 '10 at 1:52
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    yeah. Point being chewing the cud requires having a whole internal system to deal with it (extra stomachs, for example), while split hooves seems a lot simpler from a genetics point of view. Not saying that any of this can be done, just what seems more likely – yydl Aug 27 '10 at 2:24
  • @IsaacMoses Does that exist? – Double AA Aug 5 '12 at 7:20

If the genetically-engineered pig was gestated in a normal pig, then no it would not be kosher.

Rambam in Laws of Prohibited Foods, 1:5-6 writes:

א,ה [ד] בהמה טהורה שילדה כמין בהמה טמאה--אף על פי שאינו מפריס פרסה, ולא מעלה גרה, אלא כמין סוס או חמור לכל דבר--הרי זה מותר באכילה. במה דברים אמורים, בשילדה בפניו. ...

א,ו [ה] בהמה טמאה שילדה כמין בהמה טהורה--אף על פי שהוא מפריס פרסה, ומעלה גרה, והרי הוא כמין שור לכל דבר, או כמין שה--הרי זה אסור באכילה:

If it is absolutely certain that a kosher animal gave birth to something that looks like a non-kosher animal, even if it doesn't have split hooves or chew its cud, and it looks completely like a horse or donkey -- it is kosher ... A non-kosher animal that gave birth to something kosher-looking, though it may have split hooves, chew its cud, and look just like a cow or sheep, is not kosher.

I'd assume we don't distinguish between the piglet that was born with a random mutation to chew its cud, and one genetically engineered to do so.

To quote Rabbi J. David Bleich ("The Problem of Identity in Rashi, Rambam, and the Tosafists", Tradition 41:2):

The notion of identification as a member of a species is best summed up in a pithy comment attributed to R. Chaim Soloveitchik. It is reported that R. Chaim queried: Why is a horse a horse? Is it a horse because it is a horse or is it a horse because its mother was a horse? To rephrase the question: Is a horse a horse because it manifests the characteristics that are the necessary conditions for identification as a member of the equine species or is a horse a horse because its mother was a horse? R. Chaim proceeded to declare that a horse is a horse solely because its mother was a horse and explained that ancestral identity is the sole factor that determines membership in a particular species. Thus, as spelled out by the Mishnah, Bechoros 5b, identity as a member of a clean or unclean species is determined by birth and not by distinguishing physical characteristics.

As a related question, I asked Rabbi Welcher in Queens about goats that were given genes from a spider so their milk contained gossamer, is the goat still kosher? He said that products of cross-breeding (even if doing so is prohibited) remain kosher, and as the non-kosher genes need the kosher genes to produce an organism here ("zeh v'zeh gorem"), it's allowed.

  • I'm a little confused. This is a good restatement and clarification of the question, but as far as I can see does not in any way answer the question. – Brandon Jul 26 '11 at 16:30
  • @Brandon, earlier I had just fleshed out the question. Now I looked it up and answered it. Thank you! – Shalom Jul 26 '11 at 17:27
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    @Shalom A horse is a horse.. horsefame.tripod.com/mred1.html – avi Jul 26 '11 at 19:31
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    Is there a point at which the future offspring of the genetically modified pig might be considered kosher, perhaps after some number of generations? – user792 Aug 3 '11 at 3:37
  • @user792, welcome to Judaism.SE, and thanks for posting this very interesting follow-up! I think it'd work well as a full-fledged question. Also, please edit your profile and give yourself a name, unless you have some attachment to the number 792! – Isaac Moses Aug 3 '11 at 3:46

The Midrash is quoted as saying "Why is its name called chazir? Because the Holy Name Blessed Be He will return it to Israel."

A lot of commentaries learn this non literally (see here and here and here for examples). Others learn it literally. The Or Hachayim (Vayikrah 11:7), writes that when Moshiach comes the nature of the pig will change, and it will start chewing its cud. It will then have kosher simanim and become kosher.

This doesn't exactly answer your question, but perhaps when Moshiach comes the pig will be genetically modified (at least according to the commentaries that take it literaly), and be kosher.

Here's an essay based on the teachings of the Lubavitcher Rebbe, discussing why specifically the pig will become kosher again, more than any other non-kosher animal.

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    Obviously, the Midrash was really talking about bacon bits! – avi Jul 26 '11 at 5:20

No, in addition to the fact that it doesn't meet the criteria for an animal that is kosher, the Torah specifically mentions pig as not allowed:
As it's stated in Deuteronomy 14:8:

וְאֶת־הַ֠חֲזִיר כִּֽי־מַפְרִ֨יס פַּרְסָ֥ה הוּא֙ וְלֹ֣א גֵרָ֔ה טָמֵ֥א ה֖וּא לָכֶ֑ם מִבְּשָׂרָם֙ לֹ֣א תֹאכֵ֔לוּ וּבְנִבְלָתָ֖ם לֹ֥א תִגָּֽעוּ׃

"And the pig, because it has a split hoof, but does not chew the cud; it is unclean for you. You shall neither eat of their flesh nor touch their carcass."

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    Ephraim, welcome to Judaism.SE, and thanks very much for making this basic but important point! Your answer would be even more valuable if you'd cite and link to the verse you quote. I look forward to seeing you around. – Isaac Moses Jul 29 '11 at 19:40

Look in Likkutei Sichos Chelek Aleph (Parshas Shmini) P. 222 where this issue is addressed.

(link can be found here)

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    Any chance you could summarize the important points? I'd wager that most people here don't read Yiddish. – Isaac Moses Oct 10 '10 at 8:08
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    A better online source would be hebrewbooks.org/pdfpager.aspx?req=15859&st=&pgnum=236 - the one at otzar770 may have copyright infringement issues. But anyway, the Rebbe uses (instead of siman and matir, as in Shalom's response) the terms mevarer and sibah, and brings several proofs that the latter is true - that these signs are what cause the animal to be kosher. (That said, a genetically modified pig would probably fall under the category of yotzei min hatamei - something that comes from a non-kosher source - and would probably be forbidden on those grounds.) – Alex Oct 10 '10 at 19:59
  • @alex just curious why the one on hebrewbooks.org wouldn't have copyright infingement issues – Menachem Jun 3 '11 at 20:52
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    @Menachem: because Kehos granted permission for many of their sefarim to be uploaded to hebrewbooks, but not to otzar770. – Alex Jun 3 '11 at 22:46

All your answers are fundamentally flawed. First of all, what's kosher or treif is not based on looks or preconceived notions, but simanim. The OU, whom are in the hechsher business, writes:

Rabbi Belsky was asked about a salmon (a kosher fish) that was engineered with genes from an eel (non-kosher), enabling it to grow faster. Kosher fish are identified by their fins and scales. Therefore salmon is kosher, because it possesses both fins and scales. An eel is not kosher, since it does not have fins and scales. In this situation, Rabbi Belsky ruled the genetically modified salmon is kosher, since it physically resembles a salmon, and it exhibits the signs of a kosher fish i.e. it has fins andscales.

Therefore, if a pig, which already has split hooves, would chew its cud, it would pass all the simanim.

But just because it has four stomachs, doesn't make it automatically kosher like the babirusa. B’frat, it must davka regurgitate the cud vadai and have split hooves mamash. As far as the health and spiritual benefits from such genetically-modified animals, that likely retain their violent and filthy habits, that probably wouldn't change.

Another option would be lab-grown meat, in which case you could eat bacon cheese burgers. Rabbi Menachem Genack, CEO of the Orthodox Union’s kosher division, said that meat from a lab-grown hamburger could be consumed with dairy products. Since this animal is essentially soulless, this would probably obviate the deleterious health and spiritual detriments.

To answer another misconception, such an animal would not be called a pig. This is how it is explained in Toras Menachem. Even then, I doubt any chassidic or haredi Rabbi would kasher it.

However, all that being said, there is clearly an issue of maris ayin. But this can be overcome through several ways. Based on the preceding, it would appear that one would have to leave the product on the table, and the product label would clearly have to display the ingredients, hechsher, GMO status, and whether its pareve or not.

Just so you know, you can get a bacon avocado cheeseburger at Mr. Broadway in Manhatten, just don't let your Rabbi see you.


No. It would no more make the pig kosher than smashing your engine light fixes the engine.

Our Creator gave us kosher laws as a blessing, so we would know what is fit to eat and what is not fit to eat. They are not merely arbitrary rules imposed on us to make life difficult.

Therefore He gave us a way to recognize which animals are fit to eat and which are not. The two signs (for mammals) allow us to know which animals are fit to eat and which are not fit to eat.

To suggest that the cloven hoof and chewing the cud are themselves what make the animal fit to eat is the same as saying that kosher laws are arbitrary, not given for our benefit but merely a set of rules for the sake of imposing rules. This suggests a very negative view of God, which is not consistent with the Bible.

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    Brandon, Welcome to Judaism.SE! You could make this answer much more valuable if you could back it up by citing a source. – Isaac Moses Jul 26 '11 at 4:27
  • @Isaac: thanks! I'm attempting to make a logical argument (implicitly) rather than citing a source. But (as you can see) I'm new here. Is that not considered okay? (If not, why not?) I could make the argument explicit, and go back to the text of the Bible to support it, if the logic to it is not already clear enough. – Brandon Jul 26 '11 at 5:08
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    Brandon, your logic seems to be predicated on an assumption that the symbols of a kosher animal are merely indicators of an inherent kosher- or not-kosher-ness that is resident in the animal regardless of the symbols (one side in Shalom's restatement of the question). Or, at least, that pigs are somehow inherently not kosher, independent of the fact that they don't chew their cud. Neither of these assumptions is self-evidently true, so I'd say that the success of your argument would depend on citing a source to prove one or the other. ... – Isaac Moses Jul 26 '11 at 5:22
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    ... In general, around here, and especially when it comes to determining what Jewish law and tradition have to say about something (such as whether a particular animal would be kosher), it's best to cite an authoritative source that either makes your point or serves as the basis for it. Fundamentally speaking, when you're trying to determine what the Tradition says, pure logic isn't going to get you very far without an appeal to that Tradition somewhere in it. It's not like kosher-ness can be determined from logical first principles! – Isaac Moses Jul 26 '11 at 5:28
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    @Brandon the implicit logic isn't clear to me. In one case you are changing the 'thing', in the other case you are destroying something which is not the 'thing'. Are you saying its no longer a pig, or are you saying that a pig with all the kosher 'lights' still isn't kosher? – avi Jul 26 '11 at 6:08

Any pig that has been genetically modified to chew its cud is no longer a pig but a completely new animal. The test for any new animal is "Does it have cloven hooves and does it chew its cud?"

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    Note that there is a discussion about a mutant born from an animal of the other type in the Tur (for example) and it still follows its mother. – sabbahillel Sep 30 '15 at 14:26

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