The allegations against Algerian boxer Imane Khelif at the Paris Olympics raised the questions of intersexuality and its implications in competitive sports. This news organization has decided to delve into the topic to assist doctors who suspect a similar condition in their patients. No certain clinical data about Ms. Khelif have been made public, so this article does not concern the boxer but rather takes inspiration from the media controversy.
What Is Intersexuality?
Intersexuality encompasses a spectrum of variations in sexual development that lead to the simultaneous presence of typical male and female characteristics. As reiterated by the United Nations Office of the High Commissioner for Human Rights, the medical definition does not affect the patient’s self-identification of gender or sexual orientation.
“The percentage of people who fall within the intersexuality spectrum is less than 0.5 per thousand of the general population, but there are no precise statistics, given the difficulty of definition,” said Roberto Lala, MD, pediatric endocrinologist and president of the Federation of Rare Childhood Diseases.
Indeed, there is not only a strict definition of intersexuality that involves a significant presence of these mixed physical characteristics in a way that conditions the self-image of the subject but also a broad definition, said Dr. Lala. “For example, clitoral hypertrophy in a female otherwise conforming to the female gender, which does not raise doubts about identity,” he said.
Chromosomes, Genes, and Hormones
“The human body is, so to speak, programmed to take on female appearances in development and shifts toward male ones only if exposed to testosterone and other factors. For this to happen, testosterone must be produced during embryonic development, and it must function properly,” said Paolo Moghetti, full professor of endocrinology at the University of Verona, Italy.
The protein encoded by SRY, which is located on the Y chromosome, determines the development of the testicles from undifferentiated tissue of the embryonic gonads. The testicles of the embryo then produce testosterone. The absence of the Y chromosome is a common characteristic of most female individuals. However, there are individuals with a female phenotype who have X and Y chromosomes but lack SRY or have a variant of it that is not entirely functional.
Numerous other chromosomal or genetic variations can lead to alterations in sexual differentiation. “In phenotypically male adult subjects (with a chromosomal makeup of 46XY) with complete androgen insensitivity (so-called Morris syndrome), testosterone levels in the blood are elevated, above normal even for a male, but the hormone is totally ineffective, and the phenotype is totally female at birth, with completely female development of secondary sexual characteristics at puberty,” said Dr. Moghetti.
This means that affected individuals have well-developed breasts and a complete lack or extremely reduced presence of hair, including underarm and pubic hair. Menstruation is also completely absent because there is no uterus, and there are testes, not visible because they are considered in the abdomen.
“There are syndromes that are currently considered congenital but not genetic, of which a genetic origin will probably be identified in the future,” said Dr. Lala.
Some variations in sexual development can be diagnosed prenatally, such as an alteration of the number of sex chromosomes or a discordance between the morphologic characteristics highlighted by ultrasound and the genotype detected by amniocentesis. Some variations are evident at birth because of atypical anatomical characteristics. Others are diagnosed during puberty or later in adulthood, in the presence of infertility. The Italian National Institute of Health details these variations on its website, describing the characteristics that determine diagnosis and treatment.