I don't really care about natures, I love pokemon, regardless, I like to raise ones I think look good, or I think they are powerful, or they are quirky, or just for a random reason. I like it, also, I remember looking up the gender ratio once on serebii, and I might have misread it, but all larvitars are female, and every wild larvitar I've seen, has been female.
Funny story, I think Larvitars may switch gender when they change into a Pupitar, I actually think when I evolved a larvitar, it turned male, so.... that thing might happen, but it is weird if it can happen....