I admit I am neither Italian nor Catholic, but it's a good point. Maybe Columbo and his wife couldn't have kids? Then again, No Time to Die (of all the episodes) is the least to base any kind of conclusion about his background, since you could have placed any policeman in his place and the story would have remained the same -- in other words, aside from the first three minutes, it was the most un-Columbo movie of them all.