My pet DOES NOT want spritely.

Does anybody have any tips for getting Spritely for your pet? I've had more then 10 pets who supposedly had spritely in there imaginary "genes" but didn't get it, and I'm really sick of it! My friend told me to try training only agility strength and power, but that doesn't seem to be working so well! I even hatched with pets who have Spritely and I STILL didn't get it! PETS HATE ME. Help :3