When using a cub sex changer to change a cub's sex, there is a slight chance of the cub growing up to have a mane mutation. For example...

Cub is born as male, but gender swapped to female- 10% chance of shaggy, fluffy or fuzzy mane mutations.

Cub is born as female but gender swapped to male- 10% chance of maneless mutation.

Concerns?

-But I don't want my lion to have a mane mutation!
-Saofu fruits are cheap in the Monkey Shop. Plus, people love mutations! I think more people would laugh or smile at this than would be upset.

-People would abuse this feature to get mutations.
-No. Sex changers are a GB item and on top of it, you don't know if you've gotten a mane mutation until the cub is 2 years old. You can't use another sex changer at that age.

-Too annoying to code.
-How so? If you use a sex changer, just add 10% chance to tack on one of the mane mutations. I mean, I'm no coder so you may get me here, but this doesn't seem to be very tough to put in there.

You could even think of it as a "Thanks for supporting the site by using a GB item! Have a hairy woman."