Most newborn children have the typical appearance of a boy or girl, but in some cases the baby’s sex can’t be clearly identified. For others, chromosomes, hormones or internal organs may differ from those typical for male or female children. These situations can present an unexpected cause for concern for parents and may complicate matters later for the affected person themselves.

Does the child have a disorder, or is their appearance part of a naturally-occurring spectrum? How did this happen? What will it mean for the future wellbeing of the person? Does anything need to be done, and if so what, when and why?

In this website we address these questions from a genetics and biology research perspective. This information is intended to help affected people and their families with decision-making and coping strategies. Through better awareness and understanding on a scientific level, we hope that society can more adequately and fairly cater for those for whom the common categories of sex don’t apply.


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> Sex development, variations and disorders of sex development

> What is this website not about?

> Who created this website?

> Limitations of this website



Sex development, variations and disorders of sex development

This resource deals with aspects of sex biology that have an identifiable genetic cause or anatomical basis. It also deals with variations from typical male or female biology that are attributable to changes in gene structure and function. 

Because many of these conditions are congenital (that is, exist at birth), it is often in the newborn period that parents (or later the person themselves) may need to find accurate scientific information on how sex development usually unfolds in the embryo, how genetic factors can give rise to variations from male or female development, and the biological consequences of these variations. This website provides that information.

Here, we often use the term Disorders of Sex Development — DSD — to reflect the fact that atypical sex development usually involves consultation with doctors, and that altered gene function is usually the cause. A small number of DSDs have complications that call for immediate medication: it is difficult not to describe such conditions as disorders. However, in most cases there is no illness or medical emergency, so an alternative view is that atypical sex development is not always a disorder, and some find “intersex” a more fitting term (see also A word on nomenclature). Because there is no agreed terminology, and because different terms are suited to different parts of the sex spectrum, we will use a mix of terms in this resource.

The section Typical and atypical sex development deals with sex biology in plain language, and explains what kinds of variations or disorders of sex development can occur, what causes them, what to expect from them, and what can be done if help is required.

The section For clinicians and scientists (not yet constructed) provides advanced technical detail, and describes how clinicians and scientists can work together to further research that will improve awareness, understanding, diagnosis, prognosis and management of DSD.


What is this website not about?

The issues of gender identity and sexual orientation are not dealt with here, since the extent to which genetics contributes to them is not well understood, and they have no anatomical basis (see Sex, gender and sexual orientation).

We currently include little material on conditions that arise after the newborn period, for example during puberty, adolescence or adulthood. These areas will be expanded in future editions of this resource.

The material given here complements, and does not seek to replace, other sources of information regarding clinical management of DSD, or living and coping with atypical anatomical sex.


Who created this website?

This website was created by a group of Australian biological research scientists (see About us) who study the genes and mechanisms important for sex development, and how altered gene function can result in DSD. Our research is funded by the National Health and Medical Research Council (NHMRC) of Australia. The material here draws on a combination of our research findings and those of the international research community, and incorporates other publicly available information.

We developed the content of this site in consultation with Australian and international clinicians, people affected by DSD and/or variations in sex development, and science writers experienced in describing the complexities of biology and medicine in plain language (See Contributors).


Limitations of this website

Scientific research findings (which describe what is known) are not the same as medical advice (which prescribes a course of action). Therefore, readers are advised to seek the services of a qualified medical professional when considering any diagnosis or treatment options (as described in the Disclaimer).



Last updated: 27 October 2013

Edit history: Author P. Koopman 9/09; revised PK 5/11, 3/13, 5/13, 10/13