Sex Development & Maturation

Sex Development & Maturation (MTG7)

This Main Thematic Group (MTG) is dedicated to the Disorders of sex development (DSD) and the Disorders of sex maturation (DSM). These are medical conditions involving the reproductive system in both sexes. More specifically, these terms refer to “congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical.” The term has been controversial; the World Health organisation still references DSDs as intersex traits or conditions. The Council of Europe has called for a review of medical classifications that unnecessarily medicalize intersex traits.


DSDs are medical conditions involving the way the reproductive system develops from infancy (and before birth) and then matures through young adulthood. There are several types of DSDs and their effect on the external and internal reproductive organs varies greatly.

Parents with DSD children and clinicians involved in DSD treatment usually try to make clear distinctions between biological sex, social gender, and sexual orientation.

Turner syndrome

The most common disorder of sex chromosomes is the Turner syndrome (TS). The affected patients have a complete or partial lack of one of the two sex chromosomes (karyotype 45,X) and have a female appearance. However, affected patients do not go through puberty (in >75% of cases) or experience a menopause in very young age. TS is also characterised by short stature, cardiac malformations, hypertension and a series of other abnormalities including skeletal, kidney defects, lymphedema and predisposition to thyroid diseases and diabetes.


The most common DSD are characterised by anatomical features that are not consistent with the sex chromosomes: a) Congenital Adrenal Hyperplasia (CAH), which results in a person with female (XX) chromosomes having a body and genitals that have a somewhat masculine form, and b) the Androgen Insensitivity Syndrome (AIS), which means that a person with male (XY) chromosomes does not respond to testosterone in the common way. This results in a body with a variable degree of feminine appearance.


The most common DSM is the Congenital Hypogonadotropic Hypogonadism (CHH), a developmental disorder due to the lack of activation of the hypothalamic-pituitary-gonadal axis due to a defective function of the hypothalamic neurons secreting the Gonadotropin-Releasing Hormone (GnRH). This condition is 4-fold more frequent among males than females. Most CHH cases are diagnosed at the time of puberty due to lack of sexual development, but CHH may also be suspected in infancy in males with cryptorchidism, micropenis or associated non reproductive signs, such as defective olfaction and the palate, neurological or kidney defects.

If untreated or inappropriately managed, all these individual experience serious neuropsychological consequences due to the evident body differences with their peers.


The term “gender nonconforming” is used to describe individuals whose gender identity, role or expression differs from what is normative for their assigned sex at birth in a given culture and historical period. Transgender is used as an umbrella term to describe individuals, whose gender identity differs from the assigned sex at birth based on their physical sexual characteristics. Transgender males are people assigned female at birth but who self-identify as male. Transgender females are people assigned male at birth, but who self-identify as female. When a person’s identity matches the sex assigned at birth the term “cisgender” is used.
The term “non-binary” describes people whose gender identity, role or expression does not conform to the binary understanding of gender (male and female). This can be used as an umbrella term to include people with no gender (agender), two genders (bigender), multiple genders (pangender), or with a fluid gender (gender fluid), among others.

Information video for patients and healthcare professionals

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