Penile size and growth in children and adolescents with isolated gonadotrophin defiency (IGnD).

Penile length and circumference were measured in twenty boys with isolated gonadotrophin deficiency, before and during the administration of androgen therapy. Their age ranged between 3 and 20 years. Considering as normal, measurements above the tenth centile, in all the patients but four the penile length was below normal, and in two it was borderline. Penis circumference was normal in two, borderline in four and subnormal in sixteen. Regular administration of androgen therapy increased penile length in eleven out of fourteen patients with achievement of normal length in four. It is concluded that congenital lack of LH and testicular androgen activation causes small sized penises, even in the prepubertal period. Gonadotrophin deficiency should be looked for in patients with measurements below the tenth centile. Early diagnosis and institution of androgen therapy between 11 and 12 years is likely to increase penile size and prevent the psychological side effects of undersized genitals and delayed puberty.