Can't you use the "Power Items?"
Yes but if I use one on both parents I lose the 50% or whatever chance of getting the right nature
Besides the loss of an everstone, if you have both parents hold a power item, for example, give a ditto a power anklet and a Kadabra a power belt, then the baby abra will inherit EITHER the speed or the defense stat, then proceed to inherit two other stats from random parents EXCEPT for the ones being "forced" by the items, in this case Speed or Defense.
So, you're basically guaranteeing that the resulting abra will have either the speed or the defense you want, but never both. On the other hand, using only one power item will give you a chance of hatching a baby with both stats AND free up a parent to hold an everstone to pass on a nice nature at the same time.
And the only reason I've bothered to mention this is because that's what happened with my shiny Bisharp. I figured two power items meant two guaranteed stats and learned the hard way that it doesn't. Not quite my biggest FUUUUUUUUU! moment, but definitely up there! x)
The best part is, that Bisharp was born with a nature that decreases the only perfect stat she inherited. Boy, am I lucky or what!?! XD But yeah. I'm not going to complain TOO much about a beautiful shiny.