Blood Tests and DNA – Part Four by Rabbi Chaim Jachter


In the past three issues, we have discussed the admissibility of blood tests and DNA evidence in Beit Din.  In our first issue, we noted that most Dayanim rule that blood tests do not constitute admissible evidence in Beit Din to prove that a husband is not the father of his wife’s child.  In the second essay, we saw a range of opinions regarding DNA evidence expressed in four responsa written before the year 2000.  Rav Ovadia Yosef rejects its use to prove or disprove paternal identity, while Rav Shlomo Zalman Auerbach regards DNA evidence as admissible in Beit Din.  In our last issue, we presented the compelling arguments that DNA evidence constitutes acceptable proof of the demise of a missing husband.  We shall conclude our series with a discussion of the potential Mamzeirut problem inherent in admitting DNA evidence in Beit Din. 

Mamzeirut and DNA Evidence

In line with the rulings of Rav Shlomo Zalman Auerbach, Rav Eliashiv, Rav Shemuel Wosner, Rav Zalman Nechemia Goldberg and Rav Mendel Senderovic, the Beth Din of America utilized DNA evidence as an important (but not exclusive) consideration in identifying the remains of husbands who were missing as a result of the World Trade Center terrorist act (as reported in my Gray Matter 2:123)

A potential problem with this ruling is that it opens a proverbial Pandora’s Box, since once Batei Din admit DNA as evidence of a husband’s demise, they seemingly must accept DNA as evidence of parentage.  This could (God forbid) potentially open a floodgate of Mamzeirut cases (especially in Israel where even non-observant Jews are married under Orthodox auspices) in which DNA evidence indicates that a husband is not the father of his wife’s child. 

We should note that Rav Shlomo Dichovsky’s claim (cited in part two of this series) that DNA testing is insufficient to determine Mamzeirut since it is only 99.6% accurate (in 1982) is no longer valid, since currently the chance of error in a properly administered DNA test is greater than ten billion to one (see, though, the rulings of Rav Ovadia Yosef and Rav Shalom Massas issued in 1996 printed in Teshuvot Yabia Omer 10 E.H. 8).

Rav Mordechai Willig (Kol Tzvi 4:12) grapples with this problem and at first argues that we should permit an Agunah to remarry based on DNA identification despite concern that it might cause others to be declared Mamzeirim.  He notes the celebrated Mishnah (Ohalot 7:6) that states, “Ein Dochin Nefesh Mipnei Nefesh,” we do not sacrifice one soul in order to save another. 

Rav Willig presents another potential distinction that may solve this problem.  In a wide variety of Halachic areas, we do not attach any significance to that which is not visible to the naked eye.  The Chochmat Adam (Binat Adam 38:49), Rav Shlomo Kluger (Teshuvot Tuv Taam VaDaat 2: Kuntress Acharon number 53), the Aruch HaShulchan (Yoreh Deah 84:36) and Rav Ovadia Yosef (Teshuvot Yechave Daat 6:47) rule that we need not be concerned with buginsects that can be seen only with the aid of a magnifying glass.  Rav Moshe Feinstein (Teshuvot Igrot Moshe Y.D. 3:120:5) rules that we need not determine that Tefillin are square using a microscope.  Teshuvot Doveiv Meisharim (1:1) rules that we do not rely on a magnifying glass to determine that letters in a Sefer Torah do not touch each other (Mukaf Gevil).  Tiferet Yisrael to Avodah Zarah 2:6 (Boaz 3) rules that a fish whose scales are visible only when viewed with a magnifying glass is not kosher.  He similarly rules that an animal with a hole in its lung that can only be seen with a magnifying glass is not a Tereifah.  Teshuvot Even Yekarah (2:33) rules that a Tanach whose tiny letters are visible only if viewed with a magnifying glass is not endowed with Kedushah (holiness).   Rav Yosef Massas (Teshuvot Mayim Chaim 259) permits an Etrog whose blemishes can be detected only when examined with a magnifying glass.

Accordingly, one may ask how we can rely on DNA evidence if DNA strands are not visible to the naked eye.  Rav Willig suggests that a distinction can be drawn between evidence to prove the death of a missing husband (Eidut Ishah) and other areas of Halacha.  Classical Halachic sources relax the rules of evidence in many aspects regarding Agunot, such accepting hearsay evidence and the testimony of those who are normally considered invalid witnesses (such as women; see the sources and explanation presented in my Gray Matter 2:118).  Contemporary authorities continue this tradition by accepting the testimony of non-observant Jews who were raised in an environment of non-observance (see Gray Matter 2:119).  Similarly, we can argue that even though DNA evidence does not constitute evidence regarding other areas of Halacha, it does carry weight in the context of permitting an Agunah to remarry. 

Rav Mordechai Willig also suggests that DNA evidence would merely prove another man to be the father, not necessarily that the the child is a Mamzeir, since it is possible that the child was conceived through artificial insemination.  According to Teshuvot Igrot Moshe (E.H. 1:10), Teshuvot Chelkat Yaakov (1:24), and Rav Yosef Dov Soloveitchik (cited in Nefesh HaRav p. 255) a child conceived via artificial insemination is not a Mamzeir, even if the sperm donor is not the husband (many Poskim, however, disagree; see, the ruling of the Satmar Rebbe that appears in HaMaor 5724, Teshuvot Minchat Yitzchak 4:5 and Teshuvot Minchat Shlomo 3:98).  We noted last week that if a husband was overseas and his wife gave birth to a child up to twelve months after he left, we do not consider the child to be a Mamzeir.  Thus, we see that Halacha will even rely even on remote possibilities (in combination with the Gemara’s assertion that Rov Be’ilot Achar HaBaal, that we explained last week) in order to avoid problems of Mamzeirut. 

A problem with this approach is that it has never (to my knowledge) been suggested by any of the great Poskim of the modern period who have been forced to grapple with a large number of potential Mamzeirut situations.  It was also not mentioned as a viable option in the responsa regarding the admissibility of blood tests as evidence of parentage.  We should clarify that it would seem that even according to Rav Willig’s suggested approach one cannot solve every case of Mamzeirut by assuming that the child was conceived by artificial insemination.  It seems that this line of reasoning is appropriate only in combination with the assumption of Rov Be’ilot Achar HaBaal (see TABC’s Bikkurei Sukkah number 53 where we cite the insights of my student Eitan Ehrenfeld). 

Rav Willig’s suggestion might be the reason why the two great contemporary Poskim of Bnei Brak, Rav Shmuel Wosner and Rav Nissim Karelitz, rule (Techumin 21:123) that although DNA evidence may be relied on as a semi-adequate Siman to identify the remains of a missing husband, it does not constitute evidence of Mamzeirut (they do not offer a reason for their conclusion, thus their reasoning is subject to speculation).  They also distinguish between DNA evidence that matches the remains of a missing husband’s DNA and a sample taken from his personal affects (such a brush or comb) as opposed to DNA identification that is based on a comparison between the husband’s remains and a DNA sample from his parents or child (when a DNA sample is available from the missing husband they regard it as a semi-adequate Siman that is almost an adequate Siman, and when the comparison is conducted with a parent’s or child’s DNA they view it as no better than a semi-adequate Siman).  They view the former as being far more compelling even though the chance of error even in the latter case still exceeds ten billion to one.  They also accept DNA as admissible evidence even in the former case only if it is there is considerable other evidence (Raglayim LaDavar) to support the assumption that the husband is dead.

It might be that Rav Wosner and Rav Karelitz are not willing to lend credence to DNA evidence since they are skeptical about scientific assertions (they view it is subject to change, as we discussed in the first article in this series).  However, a motivation to use DNA evidence as a Halachic consideration is its potential to resolve tragic cases of Igun.  A motivation to view the latter case as less compelling is that it eliminates the creation of a precedent to admit DNA evidence as proof of Mamzeirut.  Thus, Rav Wosner and Rav Karelitz have adopted a brilliant approachapproach that one on hand allows DNA testing to alleviate the tragic plight of an Agunah yet still not open the Pandora’s Box of revealing the identity of Mamzeirim (recall from the second article in this series that Rav Eliashiv also managed to avoid using DNA evidence to reveal the identity of a Mamzeir, even though he seems to believe that DNA evidence is admissible in Beit Din).  

A Halachic basis for drawing this distinction might be the lack of precedent to compare the features of the missing husband and to those of his parents or children in order to identify the remains of missing husband.  There is, however, precedent to rely on comparisons to the missing husband’s effects such as his dental records or fingerprints. 


Dayanim were able to avoid having blood test results revealing the identity of Mamzeirim because a passage in the Gemara can be interpreted as negating the validity of blood tests proving or disproving paternal identity. In addition, blood tests can be ignored at no “cost” since there is (for the most part) no Halachic “benefit” to relying on them.  On the other hand, there is no Talmudic text that indicates that DNA does not constitute admissible evidence in Beit Din, and many people can benefit from relying on it.  Not surprisingly, we find contemporary Poskim relying either fully or partially on DNA evidence, especially to identify the remains of a missing husband.

Megillat Ester, Gan Eden and Moral Equivalence by Rabbi Chaim Jachter

Blood Tests and DNA – Part Three by Rabbi Chaim Jachter