We might not want to know the dark secrets lurking in our genes

Genetics has advanced to the point that we can sequence a person's genome, outlining their entire genetic blueprint, for a couple thousand dollars - perhaps even less - in approximately a day (provided you already have the million-dollar machine on hand).

That's far less than than the $3 billion it cost to first sequence a human genome, and many researchers agree that we're heading towards a time where we'll all have our genomes sequenced.

"That's certainly the vision of the future," says George Annas, a bioethicist at Boston University.

But there's one big problem with that: Once we're good enough at reading a DNA sequence to really interpret all the results - rather than just glean a few hints here and there - we may not want to know the answers.

The problem is that knowing the answers doesn't mean we'll know how to solve anything. There would be a high likelihood of identifying many ticking time-bombs or risks that we would still have no way of addressing. That could mean living an entire life knowing that you are, in a way, "sick."

For now, we only know that a few specific genes are uniquely responsible for certain diseases or traits and that many more genes are broadly associated with certain characteristics, though not uniquely responsible for them. But we're rapidly learning more about how genes interact to code for different behaviors, and as we do, we gain a more precise understanding of how genes can make a person susceptible to a host of diseases.

"Nobody's got a perfect genome," says Annas. "When you start looking for stuff, you're going to find five or 10 lethal genes that could kill you if you live long enough."

If we start sequencing the genomes of infants at birth to have a head start on their healthcare, we might be able to say that that infant will be at a high risk for an untreatable cancer or Alzheimer's disease. But that doesn't mean we'll know how to help that person.

"Americans live in this culture where if you find something, you want to do something about it," says Annas. He says that if we start anticipating diseases that will occur late in life from the moment of birth, "we're going to make every child someone who is born sick."

So far, DNA sequencing has proven useful when treating patients with cancer or when trying to solve a medical mystery where doctors can't figure out what's wrong with a person. And efforts like the Precision Medicine Initiative, which will rely significantly on DNA sequencing, should reveal far more about the genetic causes of disease.

But we'll have to make a decision about how much screening we want, and whether we want to know - potentially from birth - what illnesses and conditions lie in wait, even ones that we don't know how to cure.