"The subject of the lecture is the equality between men and women."
Translation:La temo de la prelego estas la egaleco inter viroj kaj virinoj.
"inter viroj kaj virinoj" makes it clear that it's about equality between men at one side and women at the other side. "inter geviroj" generally means equality between people, be it men or women.
Ooh, I see. I didn't read it like that. I rather read it as equality between all people: both men and women (which I then found kind of peculiar, because they left out nonbinary genders and such, but yea). But your interpretation makes way more sense, thank you!