At-home genetic testing

Q: I’m thinking about using one of those mail-in genetics tests. Are they reliable? – Gini W., Brooklyn, N.Y.

A: You didn’t say why you wanted a mail-order genetic test done: To find out your ancestry? To determine paternity? To find out if you are at risk for, or may pass on, any inherited conditions? The wisdom of a mail-in test depends on the info you hope to get from it and what you plan to do with it.

For ancestry: variations in your DNA can reveal where your ancestors might have come from and with whom they might have comingled. The most inclusive test (works on men and women) is single nucleotide polymorphism (SNP) testing: a large number of your SNPs (pronounced snips) are identified and compared with the SNPs of lots of other folks to determine your racial and/or ethnic background. It’s even possible to see how much of the Neanderthal genome still lives on in you!

Oops! Results can change from one service to another depending on the DNA database they use for comparison. Home genetic ancestry tests are not FDA-regulated.

For paternity: these saliva or cheek swabs use around 15 markers to compare a child and a man’s DNA, so that’s pretty good. But it takes mom, dad and the child to raise the test’s reliability to 99.9 per cent.

Oops! Labs analyzing home samples aren’t necessarily accredited or regulated; some do not do duplicate tests to verify results; and sample errors can happen with contamination in collection, shipping or analysis.

To assess disease risk: mailorder DNA tests evaluate your potential risk for genetically transmitted diseases, such as some forms of breast cancer or sickle-cell anemia.

Oops! The test cannot say for certain that you or your offspring will develop a disease (many risks are modifiable with smart lifestyle choices), how severe symptoms will be or if the disorder will progress over time. You want expert genetic counselling and topquality medical care before deciding how to act on the information.