I have just had a child born from a GP grade 1 lvl 50 and a lvl 50 unicorn which has been given grade 2, and much as I would love it to be correct  I am afraid ... checking the FAQ... it appears that it should be grade 1

Child:

http://beastkeeper.com/pet/58349

As you can see he has 6 dominant genes from his father and 4 from his mother.

From the FAQ:

Lvl 50 pet GP grade 1 x Lvl 50 pet = Child GP Grade 2 (if there are 7 or more dominant genes from parent with Grade 1) or Grade 1 (if there are less than 7 dominant genes from parent with Grade 1)

Thanks for reporting.

There was a typo in code which assigned the inheritance of grade with 6 dominant genes instead of 7 in some cases. The pets which are affected by this bug are being fixed right now.

Sorry for the inconvenience.

After some consideration, we decided to revert the affected pets back to their original grade. We can't define if these pets were affected by Mutagen or not, so it's impossible to exclude the pets who have correct GP grade but genetics was altered because of the mutations.

Thanks to all users who helped to find this bug and its consequences.