The answer is "Robert Jordan was a boomer who probably was never presented with the existence of trans people before he got too far into the series to figure out how to make his gender binary a spectrum," but they do explain that which half of magic you get access to is basically a boolean flag on your soul so presumably a trans channeler would just be someone who's soul got reincarnated into a body opposite whatever that flag was.
kinda sorta spoilers for a minor plot point
There's actually a quasi trans character, though I'm using that term very loosely here, who is a channeler. They were a heavily misogynistic man, pissed off Not Satan quite a lot by failing at something, and got their soul forcibly shoved into a woman's body as punishment. They continued to wield the male half of the Source.
The answer is "Robert Jordan was a boomer who probably was never presented with the existence of trans people before he got too far into the series to figure out how to make his gender binary a spectrum," but they do explain that which half of magic you get access to is basically a boolean flag on your soul so presumably a trans channeler would just be someone who's soul got reincarnated into a body opposite whatever that flag was.
kinda sorta spoilers for a minor plot point
There's actually a quasi trans character, though I'm using that term very loosely here, who is a channeler. They were a heavily misogynistic man, pissed off Not Satan quite a lot by failing at something, and got their soul forcibly shoved into a woman's body as punishment. They continued to wield the male half of the Source.