my guppies have NEVER eaten their fry, at all. somebody told me it was a gene they had?

[White Wolf]

i have been told that my guppies were stock from several crosses, one of which were moscow blues. i have been told that the 'moscow blue gene' represses the desire to eat their fry, and so far my guppies are proving that to be true, has anybody else experienced this before?
the fry swim freely amongst the adults almost straight after birth, and not once have the adults eaten or even chased them, they just swim together.
i have live plants for them to hide in, but they never hide.

does anybody else have guppies that leave their fry alone? or does anybody have any moscow blue guppies? it would be interesting to know if they ate their fry?