Puberty in boys should start between the ages of 12 – 14 and in girls between the ages of 11 – 13.

Some boys will always be later than other boys and there is a fundamental difference between a “constitutional delay of puberty” and a case of Kallmann syndrome. Kallmann syndrome is a very rare condition and will not be the first condition that a GP would normally suspect when presented with a case of absent puberty.

It has been common for GP’s to have a “wait and see” approach to cases of delayed puberty, assuming that puberty will start eventually. For a lot of boys this indeed would be the case. However in a case of Kallmann syndrome puberty will not commence without treatment. It is not uncommon for people with Kallmann syndrome to be dismissed by their doctors so often as late developers they loose faith in going forward with such an embarrassing condition. It is not that uncommon for men to get into their 20’s or 30’s before a correct diagnosis is reached.

Experts in Kallmann syndrome now suggest that any boy who has not started puberty by 15 or a girl not started having periods by 14 should be referred to an endocrinologist for specialist review. An endocrinologist can then differentiate between a case of delayed puberty and a potential case of Kallmann syndrome.

If a boy has not started puberty by 14 or a girl who has not started periods by 13 and the levels of the pituitary hormones LH and FSH are low there should be no reason for a delay for a referral to an endocrinologist. The presence of other signs such as lack of sense of smell, family history of “late developing” or infertility, un-descended testes at birth should make an early referral even more important. This is particularly important with women as there can be a wide range of conditions that could prevent periods from commencing and it is important to get the correct diagnosis quickly.