We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

Genetic Testing Brings Up a Surprising Topic: Incest

By Patrick Morgan
Feb 12, 2011 12:22 AMJun 28, 2023 7:55 PM


Sign up for our email newsletter for the latest science news

As more hospitals have begun using DNA testing to analyze babies with birth defects, doctors have occasionally discovered that a family's little bundle of joy is also a product of incest. Since this is a new dilemma brought on by the spread of technology, doctors are now debating how to handle these incest surprises. Geneticist Arthur Beaudet at Baylor College of Medicine addressed the issue yesterday in an article in the medical journal The Lancet. The genetic test, the single nucleotide polymorphism-based array, helps doctors identify missing genes (and can therefore help explain a child's birth defect or disability)--but it also identifies swaths of identical DNA that a child may have inherited from two closely related parents.

In the few months that Baylor has been performing these detailed genetic tests, there have been fewer than 10 cases of consanguinity -- the phenomenon of inheriting the same gene variations from two closely related people, said Dr. Arthur L. Beaudet, chairman of Baylor's department of molecular and human genetics. However, wider use of such testing in children with disabilities is expected to identify additional cases of incestuous parentage. [ABC News]

In the United States it's illegal for first-degree relatives to have sex, but when both partners are adults, it usually goes unreported. Doctors are worried about all close incestuous parings that result in a child, since such children have a much higher risk of disabilities. But Beaudet and other doctors are particularly worried about cases that involve sexual abuse of a minor.

"The concern mainly stems from the possibility of children being sexually abused in the home, most often girls between 12 and 16 years of age," he said.... Disabilities are frequent in children born of incestuous liaisons. In the past, doctors may have suspected a child was the product of incest, Beaudet said. "Now we have a routine test that we do in children with disabilities that makes it obvious." [Reuters]

At the University of Pennsylvania School of Medicine, Pathology Professor Nancy Spinner has uncovered two cases of incest since 2008, when she started using these genetic tests.

"In both cases, you see it and it causes you a little agony because you realize it could be a big problem. But when we contacted the physician to learn more about the case, in both cases it was known," Spinner said in a telephone interview.... "In one case, the father was incarcerated for rape. In the other case, there was a known product of incest," she said. [Reuters]

By law, doctors are required to report suspected child abuse. However, these laws were made before we had genetic testing technology, which is why the debate is now open. Beaudet is currently trying to gather medical professionals to create protocols for these cases.

Beaudet wrote in the letter that "clinicians uncovering a likely incestuous relationship may be legally required to report it to child protection services and, potentially, law enforcement officials" since the pregnancy might have occurred "in the setting of sexual abuse." [Houston Chronicle]

Even though few U.S. hospitals use this specific genetic test, other labs are looking to pick it up, which means that guidelines should be forthcoming as more incest revelations are inevitable. And some professional organizations are already answering the call:

A committee of Baylor, Texas Children's Hospital and Ben Taub General Hospital representatives is almost finished crafting a policy about the issues raised. Chairwoman Amy McGuire, a bioethicist, said these issues include consent, results disclosure and reporting. [Houston Chronicle]

Related Content: 80beats: What Killed King Tut? Incest and Malaria, Study Says 80beats: Darwin’s Family May Have Paid a Price for Inbreeding 80beats: Cousin Marriages May Be Taboo, but They’re Not Genetic Disasters Gene Expression: Incest vs. polygamy Gene Expression: Incest, Morality and Genetics I

mage: iStockphoto

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.