He is now denying the validity of dna tests. I don’t want to say the past 35 years of having him treat me worse than he treats his sister had anything to do with his assumptions of my dna, but he was upset to learn that I am more Irish than him. I wonder what he thought of my mother before these results…
Corporations aren't exactly known for being honest or fair, or following the law, when they have valuable data to sell. They might tell you that they'll delete your data but there's always a chance that they'll retain it and sell it under the table if someone makes a compelling offer. Or an employee could steal the data and sell it secretly, or they could have a security breach and someone could make off with it.
Why would any of that be bad? Because health insurance companies are salivating over new ways to deny your claims (or crank up your premiums) and genetic data that reveals an elevated risk of a serious condition is a damned good excuse for them to do just that.