Most newborn children have the typical features 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 child? 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 broader awareness and deeper 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.


  • Scroll down to read more introductory material:

> What is this website about?

> What is this website not about?

> Who created this website?

> Limitations of this website



What is this website about?

This website deals with how parts of the body develop differently between males and females, and the part played by genes in this development. It also deals with the anatomical variations from typical male or female biology that can occur - these are due to changes in gene structure or function. 

Because many of these variations are congenital (that is, they exist at birth), it is often in the newborn period that parents 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. As the child grows up, they themselves will want to find out more about these issues. This website is intended to provide that information.

The section Male and female sex development deals with the biology of this subject in plain language.

The section Variations of sex development, intersex & DSD explains what kinds of variations and disorders can occur, what causes them, what to expect from them, and what can be done if help is required.

For a discussion of terminology in this area, see Intersex and DSD: What's the difference?.


What is this website not about?

The issues of gender identity, transsexuality and sexual orientation are not dealt with here, because the extent to which genetics contributes to them is not well understood, and because 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.

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


Who created this website?

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

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

The content was extensively revised and updated in August 2021.


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 diagnostic or treatment options (as described in the Disclaimer).



Last updated: 7 August 2021

Edit history: Author P. Koopman 9/09; revised PK 5/2011, 3/2013, 5/2013, 10/2013, 7/2015