There's plenty of data on the effects of high powered radar on humans. Most of it resulted from stupidity like drinking beer in front of a megawatt radar dish while it was turned on. Several deaths back in the 70's and 80's, most still classified.
The CIA did investigate the
use and effect of microwaves on humans in response to a Soviet
practice of beaming microwaves on the U.S. embassy. The agency
determined that this was outside the scope of the Advisory
Committee's purview.
http://www.gwu.edu/~nsarchiv/radiation/dir/mstreet/commeet/meet4/brief4.gfr/tab_j/br4j1.txt
Before jumping on the bandwagon against this mother, I wonder if the effects could be such that they were "delayed"? If the mom comes home and the baby is "sleeping" - but breathing fine, etc. could it still have been nuked by the babysitter? I imagine that the baby still would have been in terrible pain however, unless it was in a coma or something. Regardless, whoever did this will be set on High for eternity.
The coroner's statement puzzles me as well. Does he think a microwave oven will internally cook the tissue of a chicken, a rabbit and a trout but not the tissue of a human infant? Not that dumb people don't sit on juries, but every last one of them has used a microwave repeatedly so defense won't be able to throw sand in their eyes on this point.
Then there's this claim from Arnold's lawyer --
Speaking of smells, I think I smell the distinct odor of an insanity plea.