Perhaps it's because of the age of your account; it's locked until the 7th if I remember correctly, but don't worry, I've fixed the breeding system and now you can have infinitely better offspring.
Actually, I've already unlocked it. The problem must be that it doesn't work with purchased Furrymons, as the other person mentioned... which is kind of complicated since I don't remember exactly which ones I bought and there are several that have been bred 😬
