A good starting place, encyclopedias can provide general background information and may suggest directions for research. General encyclopedias:

(Jason Goecke via Flickr with Creative Commons)
These databases provide helpful background and history, statistics, and current trends around controversial topics:
Subjects: Social & Behavioral Sciences, Health Sciences, Political Sciences, Law Enforcement Index with full-text to in-depth studies on current or controversial issues from 1991-current. Note: only 5 users at any given time.