Although the introduction of iodized salt in specific areas has reduced endemic goiter in the US, intra-uterine lack of thyroxine-like compounds still may be one cause of lifetime neurological deficits and mental retardation of progeny born to hypothyroxinemic inadequately treated mothers. In June 1970, 1,200 scientists from more than 40 countries attended the Sixth international Thyroid Conference in Vienna. The high incidence of pronounced mental retardation, multiple neurological deficits, and the prevalence of deaf-mutism in endemic goiter populations were stressed. This is a world problem. In 1960, Kelly and Snedden estimated that there were between 50 and 200 million goitrous persons in the world.’’Endemic goiter has been classified statistically as one of the world’s most important diseases.’Querido and his associates believed “that the damage to the defectives is done in the early months of pregnancy, and may at least in part be due to maternal hypothyroidism.”’Hoet, Hoet, and Gommers in Belgium reported that many years before diabetes and hypothyroidism are diagnosed clinically these endocrine disturbances may appear in the woman during gestation.“The same patient in the non-pregnant state may not show even the mildest symptom^."'^ There is a fascinating article relating goiters in the native Michigan Indians, horses, squirrels, and sheep to the poor scholastic standing of goitrous children in that area before the general use of iodized salt.’’’The thyroid is “the first endocrine gland to appear in development” of the fetus. lS9 The embryonic thyroid has not been shown to synthesize or excrete thyroxine-like iodine compounds, although minimal amounts of such compounds have been identified in association with the early histogenesis of the fetal glands’4 4 and in fetal serum by 11 gestational WeekS. 39, 5062, 121 p remature or low birth weight neonates born before 34 gestational weeks failed to have the characteristically high serum thyroxine-like iodine compounds of full-term