DISORDERS OF SEX DEVELOPMENT: WHY ARE SOME GIRLS BORN WITH THEM?

Disorders of Sex Development (DSD) refer to a group of conditions where the development of chromosomal, gonadal, or anatomical sex is atypical. These disorders can affect girls, leading to a range of physical and hormonal variations.

The causes of DSD are complex and multifaceted, often involving genetic mutations, hormonal imbalances, or environmental factors during fetal development.

Understanding why some girls are born with these conditions requires a comprehensive exploration of the genetic and physiological mechanisms that underlie sexual development.

What Are Sex Development Disorders?

 Disorders of Sex Development (DSD) encompass over 40 different conditions that occur during fetal development, affecting between 0.05 and 1 percent of the population.

DSD can result in individuals who appear female having male chromosomes or anatomy. This is distinct from transwomen, who are born male and transition to female.

The most common DSD is Swyer syndrome, where individuals have a typical female appearance and external genitalia but possess XY chromosomes and non-functional gonads, often leading to delayed puberty and infertility.

Another condition, Complete Androgen Insensitivity Syndrome (CAIS), involves individuals with XY chromosomes whose bodies cannot respond to androgens (male hormones), resulting in a female appearance.

Mixed Gonadal Dysgenesis (MGD) is characterized by the presence of both ovarian and testicular tissue, leading to ambiguous genitalia and atypical development of secondary sexual characteristics.

How Does These Conditions Affect Sexual Development?

 Typically, girls have 46XX chromosomes and boys have 46XY chromosomes. However, in Swyer syndrome, individuals have one X and one Y chromosome, meaning they have 46XY chromosomes despite having female external genitalia.

Consequently, they are raised as females. While they may have a uterus and fallopian tubes, they lack ovaries. Girls with Swyer syndrome do not menstruate and often require hormone medication to develop female secondary sexual characteristics.

Despite being chromosomally XY (46XY), with hormone replacement therapy and the use of donor eggs, they may still be able to conceive.

Individuals with DSDs often have increased levels of testosterone in their bodies. The physical female attributes occur because the Y chromosome is inactive in those with DSDs. Their bodies do not respond to testosterone, even if its levels are high, due to androgen insensitivity.

This lack of response means that high testosterone levels do not produce any masculinizing effects, resulting in a female phenotype despite the presence of male chromosomes.

 Can these differences affect women’s performance in competitive sports compared to other female athletes?

 Exposure to testosterone from birth might provide a slight advantage in sports. However, in cases of complete androgen insensitivity, individuals do not respond to testosterone, so they do not gain any athletic advantage unless they undergo specific treatments. One notable difference is that they may experience delayed closure of their bone growth plates, potentially resulting in greater height compared to typical females.

What kind of psychological support do people with DSDs need?

When a child raised as a girl learns that their chromosomes suggest otherwise, it can be a deeply shocking and disorienting experience. It is crucial to honor their unique identity and help them adjust their lifestyle in a way that empowers them to lead a fulfilling life as a woman. Recognizing and affirming their physical characteristics, such as having a vagina and uterus, is a key part of supporting them through this journey.