Studies show that homework creates stress (http://stophomework.com/pdflinks/ENC204print.pdf). Enough stress is already created throughout the school-year. Tests, quizzes, class-work, and studying are hard enough. Homework just makes students stressed out. Stress is unhealthy and can cause health problems.
Summer is supposed to be a time of relaxation and fun. A break from the year-round stress of school. It's called Summer BREAK for a reason. Summer work is stressful to students during a time that is supposed to be full of rest. One of the main purposes of summer work is to get students ready for the school year. That's what the first week or so of school is for! Please consider this, Obama administration :)