Only 6 of the children were conceived naturally. The rest were from sperm donations. Interesting that he claims that there isn't a difference for him though in how he views his offspring.
Which is silly, anyone can buy DNA test kit for 50$ and then download the result file and upload to the miriad DNA sites out there like gedmatch, myheritage so you can be easily found.
That's how the families of my relative who donated sperm (anonymously) found me and now trying to figure out who the donor is and are contacting me.
From what I can tell (which isn't much) Durov is living in France and seems to like it there. I'm not going to assume the people that are a product of his sperm donations are all living in France, but I will assume some are.
In France paternity tests are legal, but they are highly regulated and require a court order to preform at a very small number of labs that can do it. This goes back to 1994. Even going outside that system and gaining a paternity test in another country is illegal and risks a year in prison and a 15,000 Euro fine. Not that it stops questioning husbands, but hey.