Just curious, what are you afraid someone would do with your dna results? The government in America already keeps dna results on all babies born in the 80’s and later.

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.