Kallmann Syndrome Research Paper

A subset of patients with hypogonadism have isolated GnRH deficiency and loss of the sense of smell (anosmia). This disorder is called Kallmann syndrome and is usually caused by a mutation in a gene that directs the formation of the olfactory (sense of smell) system and the formation of parts of the hypothalamus. People affected fail to go through puberty unless they are given sex hormone replacement therapy and in addition usually have no sense of smell (anosmia).
Your husband may require hormonal work-up. Fertility shots can be used to normalize sperm counts, although this may require 6-12 months of treatment.
I found the below link very informative about this condition.
http://www.pituitary.org.uk/information/pituitary-conditions/rarer-disorders/kallmanns-syndrome/