HYPERTHYROIDISM, nodular goiter and other types of thyroid disease are more frequently found in women than in men. Goiter, also, often becomes strikingly manifest during puberty, pregnancy and the menopause. This apparent relationship between ovarian function and thyroid pathology has been studied by many investigators. Unfortunately the results have been conflicting. Some have reported that ovarian hormones depress thyroid function (Franck, 1937; Gardner, 1949; Heyl et al., 1934; Karp and Kostkiewicz, 1934; Kreitmar and Sieckman, 1939; Miiller and Aeppli, 1949); others, that ovarian hormones increase thyroid activity (Andersen, 1935; Chouke et al., 1935; De Amilbia et al., 1936; Desclin and Ermans, 1951); and still others have observed no distinct influence upon thyroid structure and physiology (Arnold et al., 1938; Paschkis et al. 1948). A few reports have indicated that estrogens both stimulate and depress thyroid function, depending upon the dose and period of administration (Freudenberger and Clausen...