Congenital hypogonadotropic hypogonadism and micropenis: Effect of testosterone treatment on adult penile size - Why sex reversal is not indicated

Micropenis is commonly due to fetal testosterone deficiency. The clinical m anagement of this form of micropenis has been contentious, with disagreemen t about the capacity of testosterone treatment to induce a functionally ade quate adult penis. As a consequence, some clinicians recommend sex reversal of affected male infants. We studied 8 male subjects with micropenis secon dary to congenital pituitary gonadotropin deficiency from infancy or childh ood to maturity (ages 18 to 27 years). Four patients were treated with test osterone before 2 years of age (group I) and four between age 6 and 13 year s (group II). At presentation, the mean penile length in group I was 1.1 cm (-4 SD; range, 0.5 to 1.5 cm) and in group II it was 2.7 cm (-3.4 SD; rang e, 1.5 to 3.5 cm). All patients received one or more courses of 3 intramusc ular injections of testosterone enanthate (25 or 50 mg) at 4-week intervals in infancy or childhood. At the age of puberty the dose was gradually incr eased to 200 mg monthly and later to an adult replacement regimen. As adult s, both group I and II had attained a mean final penile length of 10.3 cm /- 2.7 cm with a range of 8 to 14 cm (mean adult stretched penile length fo r Caucasians is 12.4 +/- 2.7 cm). Six of 8 men were sexually active, and al l reported normal male gender identity and psychosocial behavior. We conclu de that 1 or 2 short courses of testosterone therapy in infancy and childho od augment penile size into the normal range for age in boys with micropeni s secondary to fetal testosterone deficiency; replacement therapy at the ag e of puberty results in an adult size penis within 2 SD of the mean. We Fou nd no clinical, psychologic, or physiologic indications to support conversi on of affected male infants to girls. Further, the results of this study do not support the notion, derived from data in the rat, that testosterone tr eatment in infancy or childhood impairs penile growth in adolescence and co mpromises adult penile length.