http://serebii.net/xy/breeding.shtmlTo quote the latest update:
"Another new feature is the furthering of IV transfer. Previously, when the parent Pokémon had power items attached, it guaranteed the transfer of one of the IVs, while several IVs were guaranteed to pass down. However, as of X & Y, if you have one of the parents hold the Destiny Knot item, then 5 IVs total from either parent will be guaranteed to be transferred"
Seems like this could drastically reduce the hassle in IV breeding, but on the other hand you may not necessarily want to use it unless you're certain of the IVs you've already worked on. Seems like it could be very useful though.
