Plutarch has a “Roman Question” on the naming days of boys vs. girls. He says that before they shed their umbilical cords babies are like plants. For people interested in the debate over when life begins, this might be food for thought. Plutarch also discusses the numerical significance of women vs men and women’s affinity for even numbers. Girls are named on the day representing the cube of the perfect dyad, 2, and given that same number of names. Boys are named on the day representing the square of the perfect triad, 3, and given that same number of names.
Here’s the passage from Plutarch on the question of why boys are named after 9 days but girls after 8, courtesy of Lacus Curtius:
102 Why do they name boys when they are nine days old, cbut girls when they are eight days old?
Does the precedence of the girls have Nature as its cause? It is a fact that the female grows up, and attains maturity and perfection before the male. As for the days, they take those that follow the seventh; for the seventh is dangerous for newly-born children in various ways and in the matter of the umbilical cord; for in most cases this comes away on the seventh day; but until it comes off, the child is more like a plant than an animal.
Or did they, like the adherents of Pythagoras, regard the even number as female and the odd number as male? For the odd number is generative, and, when it is added to the even number, it prevails over it. And also, when they are divided into units, the even number, like the female, yields a vacant space between, while of the odd number an integral part always remains. Wherefore they think that the odd is suitable for the male, and the even for the female.
Or is it that of all numbers nine is the first square from the odd and perfect triad, while eight is the first cube from the even dyad? Now a man should be four-square, eminent, and perfect; but a woman, like a cube, eshould be stable, domestic, and difficult to remove from her place. And this should be added, that eight is the cube of two and nine the square of three; women have two names, men have three.