Child abuse should be in the same category as murder as far as statute of limitations goes. There should be none as the damage is just as enduring and maybe more destructive.
Statutes of limitations are usually a good thing. People do change, releiving prosecutors of the need to keep following property crimes forever, and so on but for child abuse it is not a rational thing. This thinking is akin to the thinking that women who dressed a certain way were asking to be raped. Just because we grow up and seem to be ok doesn't validate that thinking. Those of us who have the best of everything are still scarred and damaged beyond the comprehension of most.
As Mark Twain once quipped, history may not repeat itself, but it does rhyme.