AncestryDNA is appealing to many because the results can be matched (to some degree) with many well-established family trees, but major privacy concerns (about how your data is used and sold) have been present in the past. For many, this is a deal breaker. They also offer the fewest advanced tools for analyzing data, although their database is very large.
DNA tests offer a wealth of insights into your connections to family, history and geographical locations. They both entertain and encourage you to dig into what you know about yourself. The tests make great gifts to bring you closer to your family and involve you and your family in the development of a cutting-edge science at the same time. Beyond that, the information is extremely useful for adoptees, people looking for lost relatives, genealogists and for medical science. 
As a postscript, I eventually end up having an interesting chat with Titanovo about my “bioinformatics” (distilled from my 23andMe data). One of the first things I’m told is that my eyes are green (they’re brown). However, the bioinformatics got my skin type and frame/weight generally right and had interesting (albeit occasionally generic) things to say about exercise, diet, goals, steering clear of too much sugar and so on.
Most direct-to-consumer DNA test companies warn that the tests may reveal things you wish you didn’t know about your family. For example, you could find out that one of the people who raised you isn’t your biological parent or that there’s an entire branch of your family you didn’t know about. There isn’t a way to prepare for a shock like that, but you can opt out of a company’s family-matching services if you’d rather not know.
If you’re more interested in learning about the relatives you already know you have, 23andMe has a few unique tools that let you compare your DNA with your children, parents and grandparents. If multiple people in your family tree want to get tested, fill out a GrandTree, which shows you which segments of DNA you inherit from each of your tested parents or grandparents. While nowhere near as comprehensive as AncestryDNA’s family tree and genealogy tools, 23andMe’s more nuclear approach to family genetics is a great option that lets you explore your genetic relationship with more immediate relations.

DNA tests give you an educated estimate of your ethnic makeup and help inform genealogical research by verifying existing family trees and informing future avenues of investigation. Additionally, there's a possibility you'll find living DNA matches - distant cousins and other relations - who could share their family history with you to build a bigger picture of your family tree.

A. DNA Clinics do not offer free DNA testing. The service in the UK for establishing genetic biological relationships is predominantly carried out by the private sector. The NHS does not offer DNA testing for paternity or other relationships. Companies offering free DNA testing are falsely advertising the service. DNA Clinics provide the DNA test kit free of charge, with payment for the test due on return of your samples.
When it comes to proving a biological relationship between a British citizen and a family member living abroad so that they may immigrate, DNA testing can greatly strengthen the case. However, DNA evidence alone does not guarantee a successful immigration application. If you’re considering taking a DNA test for immigration purposes, we recommend you take legal advice to ensure it’s used in the best possible way.
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.
Because it is a genetic condition, FH is present at birth, meaning most people with this condition have high LDL cholesterol levels from a young age. Since many people with FH show no physical symptoms, this condition is typically diagnosed with a blood test for cholesterol. However, some people with FH may not be diagnosed until after experiencing symptoms related to early heart disease, including chest pain or heart attack.
In testing, we found that many tests have much more specific and detailed results for European ancestry than anywhere else. This is due more to the diversity of the database than size. For example, AncestryDNA has the largest database with over 10 million samples yet results for Asian ancestry are markedly less specific than results from several companies with much smaller databases, including 23andMe and Living DNA.
Similarly, if a person has contributed a clear and distinct minority of the DNA detected, that part of the profile may be referred to as the “Minor Contribution”. However, if DNA from one or more people is present in a mixed DNA result in roughly equal quantities, any statistic relating to the likelihood that any one particular person may have contributed to the DNA profile is necessarily reduced in value due to the inherent uncertainties regarding which DNA components may have come from either contributor.
TTR-related hereditary amyloidosis typically develops in adulthood, but age of onset can vary widely. People with the V122I variant typically develop symptoms after the age of 60. People with the V30M variant can develop symptoms as early as their 20s or as late as their 90s, depending on ethnicity and family history. People with the T60A variant typically develop symptoms between 45 and 80 years of age.
— Once you have chosen a test and received your autosomal results there is still a great deal more fun to be had. Independent tools and websites created by scientists and enthusiasts allow you to take the raw data provided from FTDNA, 23andMe and Ancestry DNA and explore them in astounding detail–giving you a wide variety of new admixtures, phasing options, chromosome browsers, SNP tools and connections with family across the world. Gedmatch is our favorite because they have so many wonderful and meticulously updated tools from a variety of sources. Easily upload your raw data and run your results for free (if you love the tools, don’t forget to donate and uncover even more options.)