Blood Tests and DNA – Part Two by Rabbi Chaim Jachter


In our previous issue, we presented the consensus opinion of twentieth century Dayanim not to admit blood tests as evidence that a husband is not the father of his wife’s children.  We noted that they cite the Gemara (Niddah 30a) that states that the mother provides the genetic material from which the child’s blood is produced.  They argue that this Gemara rejects the modern scientific assertion that both maternal and paternal influences produce a child’s blood.  We suggested that the motivation for this approach lies in the Dayanim’s desire not to open up a proverbial “can of worms”, as blood tests can unnecessarily (from a Halachic perspective) reveal the identity of a Mamzeir. 

This week, we shall begin to discuss whether DNA evidence is admissible in Beit Din.  We shall present the rulings of Rav Ovadia Yosef, Rav Shlomo Dichovsky, Rav Eliashiv and Rav Shlomo Zalman Auerbach concerning DNA evidence that were issued prior to the vicious World Trade Center terrorist act.  Next week, we shall discuss the debate regarding admitting DNA evidence to identify the remains of missing husbands who worked in the World Trade Center. 

Rav Ovadia Yosef and the Israeli Rabbinic Court of Appeals 

In 1986, Rav Ovadia Yosef sat in the Israeli Rabbinate’s Rabbinic Court of appeals (we discuss this fascinating institution in an essay that is available at together with two other Rabbanim of eminent stature, Rav Yosef Kapach and Rav Yitzchak Kulitz.  They were presented with an appeal of a ruling of a district Israeli Rabbinate Beit Din regarding an interesting case. 

A young man and woman lived together without the benefit of marriage.  Some time after the couple separated, the woman was discovered to be pregnant, and she subsequently gave birth to a child.  The young man claimed to be the father, while the young woman vigorously denied this claim.  The young man demanded that a DNA test be administered to prove the validity of his claim, and the wife refused to do consent.  The district Beit Din ruled that if the woman persisted in her refusal to permit taking a DNA sample from her child for the DNA test, it would interpret this refusal as an admission that the young man is indeed the father. 

Rav Yosef (Teshuvot Yabia Omer 10: Even HaEzer 13) presents the reason why the Rabbinic Court of Appeals rejected the ruling of the district Beit Din.  Rav Yosef argues that just as the consensus view among Dayanim is to consider blood tests inadmissible evidence in Beit Din, so too DNA tests should not be permissible evidence in Beit Din.  He bases his ruling on a number of passages in the Gemara that speak of a child whose father is known to be one of two possible men.  The Gemara treats this doubt as irresolvable.  Rav Ovadia argues that the fact that the Gemara does not mention blood tests or DNA tests as a possible means to resolve the doubt indicates that these two methods are not acceptable means of determining paternal identity. 

Although this approach seems a bit far-fetched, the Gemara sometimes presents theoretical possibilities, such as transportation on a “flying camel” (see Makkot 5a), in order to bring out certain principles.  In our case, the Gemara does not present a theoretical means of resolving the doubt, giving no precedent for resolving questions of paternal identity by means of DNA testing. 

Rav Shlomo Dichovsky and the Ashdod Beit Din 

In 1982, Rav Shlomo Dichovsky sat as a member of the Ashdod district Israeli Rabbinate Beit Din.  After the Beit Din had presided over a couple’s divorce agreement and Get, the husband opened a file challenging his heretofore presumed fatherhood of his wife’s two children.  After ordering the couple to perform a blood test, the Beit Din was informed that DNA tests (accurate up to 99.6% at that time) were now administered to determine paternal identity.  The DNA test revealed that the husband was the father of only one of his wife’s two children.  When the results were read in Beit Din in the presence of the parties, the wife still insisted that her husband was the father of both of their children, denying she ever having had an affair during the marriage.  The question was whether the Beit Din should regard the results of the DNA test as evidence that the husband was not the father.

Rav Dichovsky writes that this presents a conflict between two mechanisms of resolving doubt regarding paternal identity when a wife is suspected of adultery.  On one hand, the Gemara (Sotah 27a) states that in such a case we assume that the husband is the father since “Rov Be’ilot Achar HaBaal,” which may be translated as “a wife will have most of her relations with her husband.”  On the other hand, the overwhelming majority of DNA tests are accurate.  Rav Dichovsky ruled that since we are faced in this case with a conflict of two “Rovs” (presumptions created by what is expected to happen in a majority of situations) the doubt remains unresolved.  Therefore, Rav Dichovsky opined that the Beit Din cannot obligate the husband to pay child support since a Beit Din cannot coerce sometime to pay in case of doubt (see Bava Kava 46a).

On the other hand, Rav Dichovsky stated that the child is not a Mamzeir, because the level of certainty necessary to presume that the child is a Mamzeir against the assumption of Rov Be’ilot Achar HaBaal is extremely high.  In fact, the Gemara (Yevamot 80b codified in Shulchan Aruch E.H. 4:14) states that if a husband travels overseas and his wife gives birth to a child twelve months after his departure, we assume that the husband is the father and that the wife was pregnant for twelve months (!).  Similarly, reasons Rav Dichovsky, since (in 1982) the DNA test was only 99.6% accurate, there is insufficient evidence to pronounce the child as Mamzeir against the presumption of Rov Be’ilot Achar HaBaal. 

The other two Dayanim on the court disagreed with Rav Dichovsky and ruled that the DNA evidence was not admissible in this case (the order to undergo the DNA was apparently a “bluff” intended to elicit a confession from either of the parties; see Sefer Melachim 1:3:24-27 for a similar strategy employed by Shelomo HaMelech).  They ruled that the husband must pay child support despite the DNA evidence.  They argued that the DNA test does not prove an assertion that contradicts the principle of Rov Be’ilot Achar HaBaal and the Chazakah (presumption) that had existed from the child’s birth until after the administration of the Get that the husband was the father of the child.  The husband appealed the ruling to the Rabbinic Court of Appeals, which subsequently sustained the ruling of the Ashdod Beit Din.  Rav Avraham Shapira (the Rosh Yeshiva of Yeshivat Merkaz HaRav and Ashkenazic Chief Rabbi of Israel during the 1980’s) was among the prominent Rabbanim who composed the panel of the appeals Beit Din in this case. 

Rav Yosef Shalom Eliashiv 

Rav Eliashiv was asked to adjudicate a case related to DNA testing.  A wife had claimed when she was pregnant that her husband was not the father of the unborn child.  Years later, the father wished to know whether he should conduct genetic tests to determine if he is the father of the child.  Rav Eliashiv ruled unequivocally, “Since many years have passed, and a Chazakah has been established that he is the father of the child, one has no right to cast aspersions on the legitimacy on the child by engaging in testing.”

As a precedent, Rav Eliashiv cited the Rashash that we presented last week, who explains that the rabbis of the Gemara did not engage in testing to determine paternal identity at the risk of revealing that someone who was heretofore presumed to be legitimate (BeChezkat Kashrut) was a Mamzeir.  Rav Mendel Senderovic (Teshuvot Atzei Besamim 16) observes that Rav Eliashiv does not rule that DNA evidence is inadmissible evidence in Beit Din per se.  One could add that it seems he does deem it admissible evidence, since he wanted to avoid having such evidence revealed in this particular case.   

Rav Shlomo Zalman Auerbach 

The strongest advocate for the admissibility of DNA evidence prior to the World Trade Center attack was Rav Shlomo Zalman Auerbach.  His ruling regarding a case that occurred in an Israeli hospital in 1977 appears in Nishmat Avraham E.H. 4:6 (authored by Dr. Abraham S. Abraham).  Two babies were confused after birth, and all investigations could not conclusively determine the identity of the respective parents of each baby.  The hospital administration suggested undergoing DNA testing to reach a final conclusion.  Dr. Abraham consulted Rav Shlomo Zalman and Rav Waldenberg, and both ruled that utilizing the results as a consideration in the final determination of the identity of the parents of each child was permissible. 

This is quite a significant ruling, since Rav Waldenberg (as we noted last week) is a staunch opponent of admitting a blood test as evidence in a Beit Din hearing.  In addition, Dr. Abraham writes that Rav Auerbach “now” (in preparation for the publication of the third volume of Nishmat Avraham in 1993) wrote to him, “If this [DNA] test is well-known and accepted throughout the world as reliable as a result of a numerous and unambiguous tests, it is reasonable to say that the results of this testing constitutes admissible evidence by Halachic standards.”   


Whereas Rav Ovadia Yosef regards DNA evidence as inadmissible proof of parentage in Beit Din, Rav Shlomo Zalman Auebach ruled in the early 1990’s that it is admissible.  Rav Waldenberg (in 1977) and Rav Shlomo Dichovsky (in 1982) were willing to consider its admissibility.  More recently, Rav Eliashiv seemed to accept DNA evidence as admissible evidence in a Teshuva that he authored in 1999.  Next week, we shall (IY”H and B”N) discuss the rulings of Poskim regarding identifying remains of a missing husband by means of DNA evidence, particularly in relation to those victims of the terrorist attack on the World Trade Center. 

Blood Tests and DNA – Part Three by Rabbi Chaim Jachter

Blood Tests and DNA – Part One by Rabbi Chaim Jachter