A combination of flax and olive oils (I put a splash of the first, which doesn't taste so nice, in the oil I cook with) will cover all bases for most people (along with what exists naturally in fresh fruit and nuts, and in the cold water fish we eat; two meals of fatty fish each week is more than plenty, as far as fish oils are concerned).
Oils are freely converted in the body, so the high rate of contaminaton in fish oils should discourage over-use, and a fresh "virgin" vegetable oils are safer by far. The critical ingredient is Linolenic acid, which tends to be destroyed in processed foods, and so is often insufficient.
If you can't get flax oil (54% linolenic) or can't stand the taste, then other options are pumpkin seed oil (delicious) at 15% or the lesser soy, walnut and canola options.
The only other oil issue is a decline in certain conversion enzymes with age, so older readers may wish to try supplementing with gamma-linolenic (borage/starflower is the cheapest source).
I don't know why it's touted for autism, but for optimum health, one needs adequate supplies of the right oils, the main problem being we are already oversupplied with the wrong types of fat, and even a healthy fat becomes a problem if we overindulge!
If in doubt, get clued up; I rate this guy (but not necesarily his products, which are beyond my pocket) and his nutrition books are chock full of good sense, solid references, and a refreshing lack of PC:
http://www.colganinstitute.com/store/sto.../books.htm
I've got an early version of what is now called his Sports Nutrition Guide, and everyone wants to steal it; I paid fifteen quid for it in a second hand book store (and never regretted the purchase) and the current version is even cheaper, so it's got to be a bargain. Don't be put off by the title; it's an education even if you are not into athletics!
