There's a lot of "these allegations will be proven false in court" going on in this article.
My dude, there's DNA evidence. What allegations are there to disprove??
And why does it matter that it was before he worked at your clinic?? Like if someone had been found to be groping patients or stealing at their last identical job, there's no reason to be concerned they might have continued to do so while they worked for you?? No 'we'll look into this and be sure nothing untoward happened'??
"This was before he worked with us, and now we have safeguards in place, by which we mean we're aware he's a pervert and we watch him like a hawk, or whatever legal equivalent will absolve us of any wrongdoing for providing him with a target rich environment in exchange for the prestige."
It may not be CSI quality, but it is FBI quality! Those EXACT tests and types of matches were how they identified the golden state killer and identify hundreds of John/Jane Does every year these days.
Turi King, who worked on the Richard III identification, has done very great and approachable lectures on those tests and how they're used in forensic genetics. Highly recommended watch BTW, and several are available on YouTube - she has one on just those tests and how they can be used as well as discussing their strengths and weaknesses with examples.
The "I'm 3.2% Native American" stuff is (mostly) BS, but if it's identifying specific matches, it's pretty strong evidence. It's not definitively HIM until they test him specifically, but it is the exact sort of thing that should put you on a suspect list and warrant him spitting in a cup, yeah.
The only way I could see it NOT being him is if he was using a close relative as the source, but I'm not sure why he wouldn't say that once challenged. Technically, that would have fulfilled the requirements of "anonymous" and "unknown to the mother" he promised.