The ratio of omega 6 to omega 3 is way out of balance in the typical American diet. Omega 6 is very high in many commonly used vegetable oils such as soybean and corn. Excess omega 6 promotes the development of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases.
So I don't think I need to add extra 6 in my diet even if it is in balance with the 3. I also try to stick with olive oil (low omega 6) and canola (good ratio) as being healthy oil choices. The 3-6-9 that I threw out was mine. I have only ever given Omega-3/DHA to the kids since that is supposed to be good for brain development.
Here is a good explanation: http://www.drweil.com/drw/u/QAA400149/balancing-omega-3-and-omega-6.html