I just had a total slip up doing Koffing, before you reset for IVs, you save in front of an egg with the nature, gender, and ability predetermined. I forgot to do that!!! I got extremely lucky however and hit my reset on the first try for a perfect (male) Bold non-shiny Koffing. Koffing isn't really pretty as a female anyway ;)
Edit- I saved before hatching it just to check its stats its an egg right now.