Okay, so cloning is out there — but what about pushing the sci-fi or supernatural themes even further? Masha could be a witch or vampire drinking the blood samples of her guests in order to get eternal life and beauty. Maybe she's an alien from another planet.
More than likely, these guesses are entirely wrong, because while the show has strange vibes, it doesn't seem that strange. But hey, it's fun to speculate in the meantime.