I know that the mathematical probability of an Everstone-carrying Ditto passing its nature onto progeny is 50% on Emerald. But it still seems weird that out of 50 Shroomish bred, (Everstone-holding Adamant Ditto x male Shroomish) only 6 of them were Adamant. I double-checked my Ditto halfway through, and it was indeed an Adamant Ditto holding an Everstone- and yes, I was playing Emerald. I know that mathematically this is certainly possible (albeit improbable) but considering that I've done massive amounts of breeding with this Everstone- at least 200 Pokemon bred- is it possible that Everstones lose their effectiveness over time?