I see that in many Animes, there are cross-dressing (or maybe trans) characters, like Hideri Kanzaki of Blend-S, and they usually have awfully high-pitched voices. These characters in anime and manga fall into a trope and are usually referred to as "trap characters."
Why do these characters even have high-pitched voices?
I can't think of any character that falls into this trope and has their voice fall into a lower, typically male, voice register.
UPDATE: F1Krazy says that even "reverse traps" (tomboys) have voices that sound relatively masculine as compared to normal female characters.