Even if you haven't personally used their service, if any close relatives have, they already have a sizable amount of information on your genome. They maintain the equivalent of "shadow profiles" ( https://en.wikipedia.org/wiki/Shadow_profile ) as part of their data model for "ancestry" modeling purposes - for example inferring a paternal haplogroup based on data uploaded by genetic relatives. I can only hope at the…
I'm a genetic engineer at a large pharma company. Genetic engineering of human model systems is my specialty. If I were a malicious actor, I could not do anything useful with the genome of any one person. Most peoples genomes are boring and at best sway the predisposition for disease by a modest degree. Exposing infidelity is honestly the best I can come up with.
I mean ancestry.com data van be used similarly, but genetical info is inobfuscable.