Admittedly, I had never even heard of synthetic stucco until I read this article: 

The State of Oregon has taken a huge step in preventing toxic mold in new home construction with House Bill 2112-B by banning the use of synthetic stucco. Synthetic stucco has been the subject of a number of investigations including one by NBC Dateline. Homeowners have claimed the product causes water retention within the walls leading to wood rot which in turn leads to mold contamination.

Source: Bay Area Houston: Toxic Mold. When it Happens to You.

The most interesting fact is that the legislation didn't happen until a Senator's granddaughter got ill from mold...