Q: My kids gave me one of those family DNA spit tests for Father’s Day. What should I do?

A: DNA spit test. Maybe you should change careers; you have a knack for product promotion.

My kids sent me a kit as a gift too and I decided to give it a try. After a bit of spitting, I sent my sample to their lab and after a couple of months, I got my results. So, this is a good time for the PropellerHeads to weigh in.

Business for ancestry.com, 23andme.com, africanancestry.com, familytreedna.com, National Geographic (genographic.nationalgeographic.com), and dozens of similar services is booming. For about $100 (or a little more), these test kits collect your DNA (spitting or swabbing) to evaluate your genetic background. They correlate that to your ancestors’ likely geographic origins and then report back to you. Recently these have become very popular as family gifts.

Why bother? Well, say you are thinking of running for president. You may want proof that you are 1/16th Native American. A test like this could quell the fake news.

From my perspective, the services are all pretty similar in process and result, although the providers may dispute that. Results can vary based on your particular match to their reference DNA databases. Here, size may matter. These are decent places to do a little buyer’s research: bit.ly/2OtnJacand bit.ly/2kJx6Fs.

These tests are based on what is called autosomal chromosome testing. This involves matching similarities from 22 of your 23 chromosomes, making allowances for their dilution over generations. A good primer can be found at bit.ly/2NVKORP.

Be prepared. All of these services offer much more for more of your money. Once you get your DNA results, they encourage you to sign on to their full-service offerings, where they will find DNA matches, provide family tree research, offer relative connection services, and more. While these services can prove costly, combining your family history with historical records and DNA matching can yield impressive results. If you are keen on researching your genealogy and adding leaves to your family tree, this may be the way to go.

A lot of your family history research can be done for free, without DNA. Your best results probably will come from several approaches (bit.ly/2n05SLP), including interviewing family; gathering birth, marriage, and death artifacts; and looking up historical records.

Is DNA testing safe? That remains to be seen. Some companies say they will only use your DNA to help improve their customers’ results. Others make it clear that research, including new drug formulations, may be helped by your data. Just ask 23andMe about the $300 million cash infusion from pharma giant GlaxoSmithKline (bit.ly/2Okxtnf). Senator Chuck Schumer of New York thinks ethical use of DNA testing may warrant some oversight (https://nbcnews.to/2zqCYc6).

There are also stories about DNA testing revealing step children long ago swept under the rug. Sometimes, the news resulting in divorces. This PropellerHead is not sure of the veracity of these claims, but caution may be in order.

Your DNA is your essence. You are giving these companies the keys to who you are. If paying to give your DNA to big pharma (who may very well make a fortune on the next wonder-drug) works for you, fine. Otherwise, consider opting out of third-party use and research. In any case, remember: you sent your spit voluntarily.

I know you have heard this a million times before, but watch where you mail your bodily fluids.