The importance of family medical history

The necessity of family medical history for adoptees has long been a unifying point, around which even people who don't otherwise support disclosure or reunion could rally. For a long time its importance was unquestioned. Yet in recent online discussions about adoption disclosure, I have encountered a new challenge to this argument.

The following are actual user comments from a couple of recent stories in Ontario newspapers about adoption disclosure and disclosure for donor-conceived adults, and illustrate the argument:

“The idea that knowing your unknown father's medical history is going to be of any significant value is incorrect. So he had high blood pressure; what are you going to do? Start taking blood pressure medicine prophylactically? All you need to know for personalized medicine is in your own genes, not your father's.”

— Dr Dr, "Parentage is about more than DNA", Globe and Mail, October 28, 2010

“These days anyone can pay $500 and get their genome decoded, which includes a summary of your genetic risk for many diseases, and in many cases match you with genetic relatives if you opt for that. Just go to 23andme.com or similar services. The medical history reason to contact birth parents doesn't hold much water any more. The answer to what you are at risk for is in your own cells just waiting to be decoded, and the breadth and depth of what genetic testing technology can tell you these days is expanding rapidly and the price is dropping. Considering 10% or more of kids aren't fathered by the person who is supposedly their father, genomic testing is a much more accurate approach.”

— Pragmatica, "Adoptees can find mom but not dad", Toronto Star, December 10, 2009

Let's be very clear here: DNA testing for medical prognostication is in its infancy. It is no substitute for authentic medical information from actual blood relatives. You would not expect people testing the safety of cars to work only from the blueprints: they need live data from road tests, crashes, etc. And that is what DNA is: a blueprint.

And my car analogy even involves a blueprint designed by humans, which a knowledgeable engineer can fully understand! No one fully understands our DNA, and we are only now discovering the genetic basis of all kinds of diseases. What if it takes another 50 years of research to establish the genetic link between a certain string of DNA and a rare disease, a disease you might never even hear of heard of if you had family medical information?

More subtle is the fact that many published statistical associations between DNA variants and actual medical outcomes are at worst just wrong and at best offer little predictive value.

As a customer of genetic testing companies (including 23andme) and someone with a science background, I don't dispute the importance of genetic testing. But it is best used as a supplement, and not a replacement, for accurate personal medical information.