Just take all the criminal cases in which DNA was used to convict innocent people. Now imagine that with a DNS database in the background as huge as 23andMe.
And of course selling DNA data was the idea from the get go...
The age old question: how many innocent people we are ok with convicting in order to convict the guilty ones. Personally, I don't think a for profitbcompany should even play the smallest role in that.
if there is more data, the dna identification will be more precise and correct also. Ideally i want this data to be open source, and thankfull you can download your data
Akin's Laws of Spacecraft design apply. If you want to have the biggest effect on how something shakes out become an artist.
And ideas have a flow. Nentally disturbed/child->Artist->Scientist/Engineer/Academic/Professional->Everybody else. Some other diversions may apply.
The mentally disturbed are the most sensitive to society at large's edge cases, but largely incomprehensible to everyone else due to divergent world view. The Artist breathes the surreal and unarticulated, in the practice of their work articulating that which defies the aggregate capability of the majority of society to manifest. That seeds the way for elucidation, exposition, and enumeration for the current flight of society's operant effectors, who implement it, which then trickles into the pool of common knowledge.
If you're seeing an artistic work in your life, and not keeping an eye out for it's implementations. You're running half-asleep to be frank.
You can release your DNA with an open (source) license. I personally would be hesitant, similar as I would not open source my fingerprints, health records etc., even if it is forbidden to abuse them.
Or
Just take all the criminal cases in which DNA was used to close cold cases.