Of all the things Aristotle wrote, one of the things he is most often criticized for is the claim that males have more teeth than females. Aristotle writes in his History of Animals 509b (2.3.13):
“Ἔχουσι δὲ πλείους οἱ ἄρρενες τῶν θηλειῶν ὀδόντας καὶ ἐν ἀνθρώποις καὶ ἐπὶ προβάτων καὶ αἰγῶν καὶ ὑῶν· ἐπὶ δὲ τῶν ἄλλων οὐ τεθεώρηταί πω.”
This means, in my own translation:
“And the males have more teeth than the females in humans, in sheep, in goats, and in swine; and in the other species the observation has not been made yet.”
As most people already know, this claim is incorrect; men have exactly the same number of teeth as women.
Aristotle has been lambasted for reporting this false information. The British philosopher Bertrand Russell is particularly known for mocking Aristotle’s claim about women having fewer teeth than men. Russell wrote in his book The Impact of Science on Society, originally published in 1952:
“Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives’ mouths.”
The textbook Ancient Greece: A Political, Social, and Cultural History by Pomeroy et al. turns Russell’s comment about Aristotle and women’s teeth into a savage burn about Aristotle’s views on women:
“At times, Aristotle’s powers of observation deserted him when women were their subject. The twentieth-century philosopher Bertrand Russell quipped that Aristotle would not have claimed that women had fewer teeth than men if he had allowed his wife to open her mouth” (page 401 in the fourth edition).
Aristotle’s critics are certainly correct that he could have easily checked to verify whether women really had fewer teeth than men. Nonetheless, I think much of this criticism is rather unfair. Aristotle is routinely portrayed as an overconfident buffoon, but he was clearly relying on a report he had heard from someone else that he thought was based on observation. Aristotle evidently assumed that the report was correct and did not bother to verify it for himself.
Now, we might blame Aristotle for not bothering to verify the report himself, but, honestly, I don’t really blame him for not asking his wife to open her mouth so he could count how many teeth she had. After all, looking in someone else’s mouth and counting their teeth is really weird. I can only imagine how awkward that would be, both for Aristotle and for his wife.
Indeed, I seriously doubt that Bertrand Russell personally counted his own teeth and his wife’s teeth to make sure that they really had the same number of teeth. I strongly suspect Russell did exactly the same thing as Aristotle; he heard a report that men and women had the same number of teeth and he assumed that it was true.
The only real difference between Aristotle and Bertrand Russell in this regard is that the report Russell heard happened to be correct and the report Aristotle heard happened to be wrong.
https://www.quora.com/Why-did-Aristotle-...h-than-men