As admin for a surname DNA project I frequently contact people asking them to join the project and test their DNA.
Disappointingly most of the time ....crickets.
There are a couple of family associations, one claims the same ancestry as mine, another is a small geographical group whose origin is only speculated not known.
I contacted seven males of the latter, thanks to the help of one of the female members, and my request was met by crickets.
I can only think of two reasons a person won't test their DNA: Money and Fear.
In many cases I have even offered to pay for the test. I have actually paid for three (complete strangers). Still crickets.
Then there is fear. Fear that perhaps they might find out something that they don't want to find out, such as bastardy or that they actually don't have the ancestry they so proudly claim.
Or fear that their DNA will be used by the authorities or insurance companies.
To my knowledge, genealogical DNA is not entered into a national data base, unlike military DNA. And the only info the testing lab has on genealogical DNA is the kit number, which they send back to FTDNA, or ancestry where it is then matched with the name.
I am also aware that apparently the vast majority of people have little interest in genealogy, and are too busy trying to survive and prosper, or just never thought of genealogy as a high priority.
I have three children, 11 grandchildren, two great grandchildren and nary a one of them has shown any interest in genealogy, they are too preoccupied with what is going on now, and worries about the future.
Positive side. I found a person who does not share my surname, but shares my rather unique haplogroup, down to the termnal SNP, lacking funds they let me test Y37 and SNP. Their family transited the same county, only miles apart, as another member of the project with the surname and both have a unique and rare mutation, within the unique haplogroup.
Anyone have any thoughts as to how to overcome these objections, or can think of objections not already mentioned.