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DNA Test Inconclusive

Identical Twins Both Forced to Pay Child Support: DNA Test Inconclusive

Identical twins have been a source of curiosity since time immemorial.

Although known mostly for using their uncanny similarities to engage in harmless pranks, some commit serious crimes.

When one is caught, he or she can pin the blame on the other, causing confusion among law enforcement.

Double trouble

identical twins DNA testing

The Brazilian twins who were both forced to pay for child support are just one example of this mischief.

Although they were both held equally responsible, others have gotten away with crimes precisely because they were identical twins.

In 2009, drug smuggling charges against Malaysian identical twins were dropped after police failed to identify the culprit conclusively.

If found guilty, the sentence would have been death by hanging.

The same year in Germany, DNA collected after a burglary at high-end fashion store KaDeWe led to an arrest.

Police later realized the suspect had an identical twin. After failing to link either one to the crime definitively, they were both released.

Legal and moral dilemmas

Legal and moral dilemmas of twins

Before a successful conviction, the prosecution must prove beyond a reasonable doubt that the accused committed the crime.

Accusing one identical twin makes this an uphill task. If both deny, or even admit, to committing the same crime, a dilemma arises. Prosecutors know for sure one of them did it, but which one?

Holding both of them responsible, as in the Brazilian paternity case, might sound reasonable.

After all, they both know exactly who the guilty party is, but willfully decide to deceive authorities.

A moral argument made by the German court in the KaDeWe burglary case concerned this very dilemma.

In the end, they decided freeing one guilty party was better than locking up an innocent man.

What does this mean for victims of crimes perpetrated by identical twins? Is it fair for their perpetrators to get away with the crime because DNA tests are inconclusive?

Are identical twins 100% alike?

Scientists and law enforcers have been hard at work trying to solve this conundrum.

Identical twins share the same DNA, so is there any way of forensically telling them apart? Scientists have been trying to study conditions that make identical twins phenotypically different.

One theory holds that differences in their genotypes could be used to tell them apart in DNA tests. It also maintains there’s a small chance that one twin embryo might slightly mutate after splitting from the fertilized egg.

Specific DNA tests might then be able to pick these slight variations.

One’s lifestyle might also influence some epigenetic factors. For example, if one identical twin has been smoking for years and the other hasn’t, some differences might appear in tests. 

Another method being pursued involves studying the entire human genome code, which contains 3 billion letters.

Standard DNA tests were developed long before the human genome was decoded in the year 2000. They only needed small snippets of the DNA structure to differentiate between two individuals conclusively.

New DNA tests were developed after the genome project, which compares the entire genome sequence.

No matter how identical two people are, chances are, there are slight variations in how the 3 billion letters are replicated. These variations are also transferred to children, so the Brazilian paternity test could have been solved this way.

Although it’s a better method, there are identical twins whose genomes are similar. 

Cost as a factor

identical twins

The new types of DNA tests meant to differentiate between twins are prohibitively expensive.

Eurofins Scientific, a laboratory in Brussels, is a pioneer in this field. Although it doesn’t say how much a genome comparison DNA test costs, sources claim the amount is in the hundreds of thousands of dollars per test.

Most prosecutors would be hard pressed to justify spending such funds on tests that might still turn out to be inconclusive.

Besides, to tell identical twins apart, more than one test is often required in such situations.

Even if DNA tests are successful, judges might still refuse to allow them as key evidence.

The defense might claim the technology is still new and hasn’t been thoroughly tested.

Hope for future breakthroughs

identical twins dilemma

There are other types of research being conducted. One involves studying a subject’s microbiome.

Evolutionary biologists have determined that every human on earth has distinct bacteria. By sweeping a crime scene and analyzing its microbes, it’s possible to isolate those left behind by criminals.

However, unlike standard DNA testing in which samples left at a crime scene remain the same for years, microbiome change. This depends on factors such as diet and medication being taken. If one changes their environment or starts taking antibiotics, their microbiome composition could change significantly. This makes it harder to trust as a crime-solving tool.

All hope is not lost, though, because advances in forensic technology always bring immense benefits to law enforcement.

When standard DNA testing became widespread in the 1980s, a lot of cold cases were suddenly solved. By the same logic, future innovation might make it easy to differentiate between DNA from identical twins.

The only drawback might be the expiry of the statute of limitations for some crimes. 


identical twins DNA testing

From the Brazilian paternity case, it’s easy to conclude that identical twins share 100% of DNA. This is not entirely accurate.

As scientists continue researching on the matter, they keep coming up with possible points of deviation. With more funding, and more identical twins volunteering for research, it’s only a matter of time before a breakthrough is made.

One thing DNA tests can do reliably is prove that two people are identical twins or just siblings.

If you need to be sure whether someone is your sibling or half-sibling, for personal or legal reasons, you need a sibling DNA test.

Read our guide to the best sibling DNA tests for the best recommendations.

About the Author Charles McKnight

I'm just another amateur genealogist investigating my American-Scots-Irish lineage. I built MyFamilyDNATest.com after buying all of the leading DNA tests to discover everything I could about my family history. Hopefully, this site will save you time and demystify the emerging science of DNA-based genealogy, for your family project.

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