At-home paternity tests have been around much longer than other direct-to-consumer DNA tests. Most of them require you to collect cheek swab samples from a prospective father and child, which you then send off to a lab to determine paternity. For non-legal use, these tests can cost as little as $15, but tests that provide verified results that are admissible in court cost a few hundred dollars. 
DNA profiling can also be useful for those who suspect there may be inheritance disputes over their estate once they have passed away. It provides a record that can be referred to long after someone’s death, even when all physical traces of DNA have gone. Therefore, if there is an unexpected claim for inheritance from an alleged relative, your DNA profile can be compared to that of the claimant to prove or disprove a biological relationship and the inheritance rights.

With a 16-day turnaround, MyHeritage DNA was one of the first companies to send back our test results, but I found the contents of my ancestry report to be a bit off, especially when compared to my geographic ancestry reports from other companies. I was born in Korea and therefore expected at least a little of my Korean heritage to make it onto my ancestry map, as it did with other services, but MyHeritage didn’t report any Korean heritage. 
The 23andMe sample collection kit is extremely easy to navigate. However, it can take a while to work up enough spit for the saliva sample tube, especially since you can’t eat or drink before or during sample collection. Even so, most of our testers preferred the saliva samples over the faster but more painful cheek swabs that many other companies use. Registering the kit on 23andMe’s website was also simple. Each kit comes with a sample return box, which you can just drop in the mail after sealing your sample. After that, you wait for your results.
Family Tree DNA (the longest running testing company) offers a well-established database of “cousins” and advanced tools for exploring your results. MyHeritage offers the ability to sync your results with your family tree research in a very unique way. Both are a good choice, but since every person’s needs are unique we suggest you read the full guide before deciding.
In our tests, we did find consistency across our results on the continental level. For example, my ancestry is exclusively East Asian, but 23andMe breaks it down into 80 percent Korean, 10.5 percent Japanese and 0.8 percent Chinese, with the remaining 8.7 percent in broader categories. However, Ancestry reports my DNA as 98 percent Korean and Northern Chinese, with only 2 percent Japanese. National Geographic places 85 percent of my ancestry from Northeastern Asia and 14 percent from the South China Sea region, with my DNA most closely matching the Korean and Japanese reference populations.
The technique of DNA profiling was developed by Alec Jefferys in the mid-1980s and is based on the analysis of markers in DNA known as microsatellites or Short Tandem Repeats (STRs). These markers are found at specific points (also called loci) in everyone’s DNA and they’re motifs of two-six bases (the units that make up our genes) that are repeated numerous times. The exact number of times these markers are repeated differs between individuals, but members of a family will share the same or a similar number of repeated markers, depending on how closely related they are.
The components of the STR profile are represented as data consisting of a series of peaks. For each location (locus) along the DNA molecule there will usually be two peaks, one from each parent, representing STR components (alleles) with differing numbers of repeats. If an allele with the same number of repeats is inherited from both parents, only one peak will be present.
Companies like Embark, Wisdom Panel and many others offer genetic health risk screenings, trait analyses and breed percentage information for dogs. These canine ancestry tests allow you to confidently state that your mutt is part Irish wolf hound and give you key information about your pet’s heritage for insights into potential health issues. For example, if you find out one of your rescue dog’s parents was likely a purebred boxer, you could speak with your vet about breed-specific needs. Basepaws DNA CatKit promises information about your cat’s breed and traits with just a hair sample, though it offers swab kits for hairless cats. The kit also tells you how closely related your kitty is to wild cats like lions, tigers and ocelots.

On all platforms except for National Geographic, you can initiate a search for relatives, though some services let you upload your National Geographic results for further analysis. The software continually searches for DNA matches as more people share their results. This feature may be useful if you're building a family tree or looking for relatives you've never met; otherwise, it may more of a nuisance. You can opt in or out at any time, and the DNA service doesn't share your contact information. Relatives can message you through the software, though. If you already use genealogy software, you may be able to download your results and upload them into your preferred program. Otherwise, AncestryDNA and others featured here have family tree software that you can easily link.
This is another feature of these genetic-testing sites – they are littered with caveats and disclaimers, forever emphasising that they’re not actual “diagnostic tests” and, if you are really concerned by your results, to seek further advice from your GP or another health professional. As has been pointed out by McCartney, when anything looks serious, ultimately it’s back to the very GP and exact NHS infrastructure that these kits profess to smoothly bypass.

Men have an X and a Y (chromosome) that are paired together. Women don’t have the Y, they just have two X’s. A child’s genes come from a mix up and recombining of the two parents. So a girl child will still end up with two X’s but some bits of them will come from the father’s X and some from the mother’s. A boy child on the other hand may have some bits of X from both mother and father, but his Y will have just come purely from his father – virtually unchanged. That makes Y-DNA such an exciting possibility for genealogy where you want to follow the paternal (surname) line. You could expect that Y-DNA will therefore pass virtually unchanged from father to son through the generations, meaning that the Y-DNA of a man’s g-g-g-g-grandfather will look very much like that of his own Y-DNA – with some little changes.