Dr Peat goes into detail about the effects of omega-3 oils on babies. He doesn't just think they are non essential but also thinks they are harmful
This is an extract which starts around 45mins
“I think all of the major allergic symptoms are increasing but some studies show that unsaturated omega-3 fatty acids in a woman's diet when she's pregnant seriously increase the allergies of the baby. So it isn't just the food supply is changing but the human supply is being sensitized by the stressful things in our national diet.” Ray Peat
“Experimental evidence shows that polyunsaturated (omega-3) fats retard fetal brain development, and that sugar promotes it.” Ray Peat Newsletter, Sugar Issues - Nov 2011