@Dex Stewart
Most of the mega forms are humanoid, and I think that’s due the writers/designers because of the
Bishōnen Line trope (basically the the more powerful something is, the more human it looks). Also, they know that their target audience, hence why Adventures season 1 had a cat fight near the end.
An in-universe reason could be that the human world has some influence on the digital world, hence why angels, devils and breasts are a thing in it.
@Darth Prime
They literally don’t reproduce outside of dying and coming back as a baby (or never and just be absorbed in Tamers). There’s no reason for there to be genders in that world outside of human influence, who aren’t naturally in the digital world.