The natural history and clinical findings of a probably X-linked recessive growth disorder, found in 7 affected males from 2 generations of the same family, have been described. Growth was normal for the first 2 to 4 years of age but then fell below normal curves. Bone age was retarded, corresponding to height age. Spontaneous puberty occurred at the expected age and was accompanied by a growth spurt. All patients had a similar pattern of anomalies consisting of a round facies, slight antimongoloid palpebral slant, hypertelorism, short stubby nose with anteverted nostrils, broad upper lip with marked philthrum, inguinal hernia, undescended testes, and a bifid scrotum with a scrotal skin fold extending ventrally around the base of the penis. The natural history demonstrated a favorable prognosis for ultimate height, sexual and mental development, and fertility.