Four male cousins showed clinical and biochemical features of X-linked recessive congenital adrenocortical hypoplasia. In addition, they showed varying degrees of androgenic precocity. One was virilised at birth. Another showed advanced growth and skeletal maturation. The remaining two had genital measurements greater than normal for age and showed raised testosterone levels, although pituitary gonadotrophins seemed normal and there was no response to luteinising hormone-releasing hormone testing. It is suggested that in X-linked adrenal hypoplasia, intrauterine adrenal androgen deficiency results in abnormal priming of the pituitary 'gonadostat', leading to an abnormal feedback with excess testosterone production and nonprogressive virilisation.