So for people wondering about the impossible genders on pokémon, you don't need to hex edit, you can do it with some minor glitch in PKHeX (you can do even without illegal mode but it's not very viable since you'll have limited options anyway).
1. Pick any pokémon and put the gender you want on the final pokémon. If you already have the pokémon you want to change the gender saved, open it then change the species into one you can change the gender.
2. Once you put the gender on the random pokémon, type the name of the pokémon you want to transfer the gender to in the species box (if the game offers to auto-complete, feel free to but ONLY pressing the arrows, if in doubt just type the name completely), press the collapse button on the Species, then click the white area of PKHeX.
3. Click any of the writable boxes under Species.
4. The species should update but nothing else. You'll have to fix the nickname, but otherwise done.
Like I said before it works on normal PKHeX but it also won't update the possible abilities so you'll be limited to the one you use for the gender, so you'd better use PKHaX. QR for pic related:
http://i.imgur.com/fOXDm4K.png 