What about that most infamous claim, that women have fewer teeth than men? At first glance, one wonders (as does M.) how such a claim could serve an ideological purpose. How are the interests of men advanced at the cost of women by the belief that they have more bicuspids and molars? But more importantly, M. points out that there is some evidence to suggest that Aristotle's claim about teeth is actually a testament to his careful observation rather than evidence of apriorism in his science. Although the evidence is speculative, there is some proof that the diets of ancient Mediterranean women were deficient in vitamin C and D, deficiencies which resulted in diseases such as scurvy, osteomalacia, and osteoporosis, especially in pregnant and lactating women.5 No one knows exactly what Aristotle saw when he looked into the mouths of Mrs. Aristotle and her friends, but if he consistently saw fewer teeth that would hardly have been implausible given what we know about diet, calcium deficiency, and tooth loss.

Bryn Mawr Classical Review 2004.09.19 Robert Mayhew, The Female in Aristotle's Biology. Reason or Rationalization. Chicago: University of Chicago Press, 2004. Reviewed by Thornton Lockwood, Sacred Heart University

Note that since Aristotle was about as close to an empiricist as you'll find those days, and discovered many exciting things about animals through direct observation, it's unlikely that this mistake was due to not having checked.