Earlier quoted context omitted.
Genetic testing used to be very expensive: $3B to sequence the human genome. So Ancestry/23/etc. tried to guess certain properties based on very sparse features of your genome, which is hard. But today, whole genome sequencing cost is approaching $100. This cost reduction will upend this industry, in my opinion.
That's not the point. The point is: at 19 USD per share you nearly buy at a valuation (8 billion) at which the institutional investors bought Ancestry ($4.7 billion) and 23andMe ($3.5 billion) Also: 23andMe had declining revenue in the past years and does only make around 200 million revenue. You buy a business at a valuation at 8 billion which makes only around 200 million revenue.
(People complain that Facebook etc have become big and powerful by sucking up all your data, but at least Zuck didn't charge you for the data.)