I happened to see this in today’s newspaper. They haven’t posted this weekend’s Ask Marilyn articles online yet so I’m going to type it up here.
“Say I have a 50% chance of inheriting a rare terminal illness, and I can be tested to learn whether I have the gene. If the test is positive, and I have the gene, I don’t want to know. yet, if the test is negative, and I do not have the gene, I do want to know. What should I do?
–S. Stephens, Hampton Cove, Ala.
You could arrange to take the test with these conditions:
After the test, the doctor privately flips a coin marked “positive” and “negative.” If both results–the test and the coin flip–are negative, the doctor tells you the test result.
If either result is positive, or both are, you are not told anything. So you will not know whether the test result was positive or whether it was the coin flip that was “positive.”
If you wish, you can ask the doctor to flip the coin a second time. Again, if both results are negative, you hear the test result. if either is positive, or both are, you hear nothing.
Over the years, you can ask the doctor to flip the coin as many times as you wish. If the test result was negative, you will be likely to hear it before long. But if you want to stop at three flips, you can. Regardless, if the test result was positive, you will never know for sure.”