A Dream Deferred: How access to STEM is denied to many students before they get in the door good | The Urban Scientist, Scientific American Blog Network

http://blogs.scientificamerican.com/urban-scientist/2013/01/24/a-dream-deferred-how-access-to-stem-is-denied-to-many-students-before-they-get-in-the-door-good/

This is a great article by a scientist who describes the barriers she sees that are preventing disadvantaged students from being more involved in science. Sometimes it's "just" a lack of resources, but other times the barriers range from benign discouragement to active exclusion by people in gatekeeping roles.