How does one tell what gender a Fallen is?

In a lot of the Destiny lore, there are a number of wiki pages that talk about each prominent Fallen member’s gender, like if they are male or female.

Mithraxx is a male, Eramis is a female, etc. But what isn’t clearly explained is how we know these prominent members are male or female. With Eramis, it makes sense because we have heard her voice in-game as feminine. But I don’t recall ever hearing Mithraxx’s voice, or some other voices like Atraks-1. Yet the wiki has a clearly defined way to identify each Fallen member’s gender, so I’m asking, how does one tell what gender a Fallen is?