Science and the Legal System

It takes time for the law to understand a scientific principle. We may take finger prints and DNA as cast in iron evidence today, but that takes time. Carl Zimmer talks about one such instance involving the famous actor, Charlie Chaplin, in his book on heredity, She has her Mother’s Laugh. A serial womanizer, Chaplin had an affair with Joan Berry, got bored with her, and dumped her for the next girl.

 

Berry, however, would not go away quietly. In 1943, she filed a paternity suit claiming that her in-the-womb baby was Chaplin’s and demanded he pay for the child’s upbringing. Back then, DNA comparison wasn’t an option, so lawyers tried an inherited trait as a test instead: the blood type.

 

At that time, scientists knew that the blood variant proteins (A, B and O) had certain characteristics: A and B both dominated over O. This implied certain patterns: if you got A from one parent and O from the other, you’d be an A. To be an O, you needed an O from both parents. Conversely, a child with blood type B must have one of its parents with B: there was no way parents with A and O could have a child with B.

 

While not covering all scenarios, this meant the blood type could still rule out certain combinations. Hoping theirs would be such a case, Chaplin’s lawyers demanded such a test with Berry, her child and Chaplin. As luck would have it, theirs was one of those impossible combinations.

 

Case closed? Not quite. Blood type based reasoning was still a new concept, most jurors didn’t understand it, and judges didn’t know it well enough to declare it as cast in iron. Ergo, the jury got deadlocked. A retrial followed, and this time the jury ruled in favour of Berry: they declared Chaplin to be the father! The Boston Herald was aghast:

“California has in effect decided that black is white, two and two are five and up is down.”

Nonetheless, the verdict stood. It was the end of Chaplin’s Hollywood career.

 

At the other end of the science-law spectrum is the time when a supposedly true scientific principle turns out to have exceptions.

 

In 2003, Lydia Fairchild had to get a DNA test to get welfare benefits: the DNA test would prove if her kids were really her’s, which would then determine the welfare benefits she was entitled to. The test came back showing the 3 kids were her husband’s, but not her’s!

 

The law came down heavily: had she kidnapped the children? Wasn’t she guilty of welfare fraud? Fairchild desperately got the children’s birth certificates, indicating she had delivered them in hospitals. But how could DNA be wrong? And so most lawyers refused to take her case. Except for one.

 

And then Fairchild had a fourth child. This time, a court appointed officer was there to witness the birth. He oversaw a blood sample drawn from the baby for a DNA test. Stunningly, the baby’s DNA didn’t match Fairchild! Even though the court officer had witnessed the birth and the blood draw, the court decided that DNA could not be wrong.

 

And then Fairchild’s lawyer heard of another woman, Karen Keegan, who had faced the same situation: the DNA said her children weren’t hers, though they were her husband’s. In Keegan’s case, the discovery happened when she was being checked as a possible organ donor for one of her children. So Keegan and the doctors were determined to find out what was going on (after all, it was an organ transplant/life-and-death matter). And they found that Keegan was a “chimera”: at conception, her mother had twin embryos. But very early, those twin embryos fused into a single child (Karen). And thus, Keegan ended up with two sets of DNA/cells at conception: one from each now-fused twin (parent?!). The doctors now compared cells from multiple parts of Keegan: most didn’t match her children, though one set did. The kids were her’s, after all.

 

Fairchild’s lawyer wondered if she was a chimera too. He demanded his client get the same tests as Keegan. Her skin, hair and saliva samples didn’t match her kids. But a cervical smear sample did. And so, Fairchild got to keep her kids too.

 

Heredity works in strange ways. In the chimeras, it’s impossible to say if the parent-child were also aunt/uncle-child! Or as Zimmer wrote:

“We use words like sister and aunt as if they describe rigid laws of biology. But despite our genetic essentialism, these laws are really only rules of thumb. Under the right conditions, they can be readily broken.”

 

If it’s so counter-intuitive even to scientists, can we really blame the law/legal system if it can’t keep pace?