7/31/2019 Using DNA Evidence in Halacha Broyde

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Using DNA Evidence in Halacha

Michael J. Broyde

Jewish law, like every legal system weighs and evaluates evidence, from eye witness testimony to circumstantiaevidence. This shiur will explore how halacha weighs scientific evidence generally and DNA evidence specifically inmatters far and wide, from family law to determinations of death, and places DNA evidence into the historical context ofthe many other forms of scientific evidence Jewish law has encountered, from dental evidence to fingerprints to blood

type testing.

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Shulchan Aruch Even Haezer 4:14

A woman whose husband was overseas for more than 12 months and she gave birth after 12 months, the child is a

mamzer, since a fetus does not gestate more than 12 months.Rama: But within 12 months, one need not be suspicious, as

we say the fetus gestated so long in its mother. Specifically, this is only if we saw no impropriety, but if we saw immoralconduct by the mother, then we do not say that the fetus gestated so long and we suspect [that the fetus is a mamzer].

Questions:

1. Why do we assume that the child from a 11 month pregnancy is still the fathers? [Assume that pregnancies that

last longer than 42 weeks occur only 1 in 10,000 times and assume further that pregnancies that last as long as 50

weeks are but 1 in 2,500,000, but that they do occur. Seehttp://www.time.com/time/magazine/article/0,9171,797153,00.html]

2. What is the Rama adding to this? Why is his insight so important? Is there a difference

between statistical evidence to confirm or determine? What about determining if someone

is dead or alive? Does it matter if we already knew that his life is in jeopardy and the only

question is did he actually die? Does it matter if we have no evidence at all, but just

statistics?

3. Is Rov stronger than Chazaka or Chazaka stronger than Rov (Pesachim 9a)? What exactly is

a majority? Is 99.999% stronger than a chazaka?

4. Consider the following unrelated secular law question: A woman is raped and we are looking

for the rapist. There is a DNA match from a data base to a person with a match likelihood 1

in 12,000,000. (But that person has an ironclad alibi and no other evidence linking him to

rape.) Would you convict? If the number was 1 is 120,000,000 would you convict?

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There are three types of ways to recognize an object: Excellent indications, middle indications and poor indications and

it is clear that excellent indications are valid as a matter of torah law.

http://www.time.com/time/magazine/article/0,9171,797153,00.htmlhttp://www.time.com/time/magazine/article/0,9171,797153,00.html

7/31/2019 Using DNA Evidence in Halacha Broyde

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