Endocrine Abstracts

The Endocrine Society has published guidelines on the endocrine treatment of transsexual persons (J Clin Endocrinol Metab 2009 94 3132–54). For adolescents with gender identity disorder (GID), the guideline recommends that suppression of pubertal hormones start when girls and boys exhibit physical changes of puberty (confirmed by pubertal levels of estradiol and testosterone, respectively), but no earlier than Tanner stages 2–3. In practice, this means assessing the onset of puberty in girls by evidence of breast ‘budding’ and in boys, an increase in testis volume from 3 to 4 ml. Increase in height velocity predates conventional signs of puberty in girls but such auxological data is seldom available. The age of onset of puberty in normals ranges from 8 to 13 and 10–13 years in girls and boys, respectively. Furthermore, puberty is probably starting earlier now, especially in girls. Sex steroid levels increase according to Tanner stages but for random measurements in individual subjects, these would not confirm the physical changes.

The debate about early versus late suppression of puberty in GID must recognise the variability in puberty onset and tempo and the imprecision of gonadal steroids as biological markers. Focus should be on predicting the irreversible, late physical changes as GnRH analogues can halt and even reverse early changes. For MTF transsexuals, voice ‘breaking’ and mandibular growth are irreversible and disturbing long-term. However, these are late events occurring between stages 3 and 4. The advocates of early versus late puberty suppression may find there is common ground once the characteristics of normal puberty are considered in a practical context.