People keep bringing up hyperandrogenism as though it's relevant to Semenya, an idea reinforced once again by the 2016 article now posted here, which is unfortunately full of all sorts of misinformation peddled by Joanna Harper. So I'm reposting info already on other threads in hopes of setting the record straight here too:
Hyperandrogenism is a condition that affects only biological females with female sex chromosomes & female reproductive systems. To have hyperandrogenism, a woman must have ovaries or at least one ovary. Semenya can't have hyperandrogenism because Semenya has XY chromosomes, functioning testes & no ovaries.
Women with hyperandrogenism have testosterone levels & sensitivity to it that's higher than other females, & this can lead to some viriliziation. However, they do not have T in the male range the way Semenya does because, unlike Semenya, they do not have testes. Nor do they have male androgen receptors & typically-male sensitivity to T like Semenya has.
The most common cause of hyperandrogenism is polycystic ovary syndrome or PCS. As its very name shows, PCS requires ovaries or at least one ovary.
Hyperandrogenism in women can also be caused by non-classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency (NCAH). NCAH affects both males & females, but females with NCAH still have ovaries (as well as all the other female reproductive organs), no testes.
Women with hyperandrogenism for whatever reason typically present with acne, male-pattern baldness/receding hairlines & hirsutism, which Oxford defines as "abnormal growth of hair on a person's face and body, especially on a woman." Semenya clearly does not have acne, a receding hairline or male-pattern baldness, or hirsutism; this is evident in all the photos & videos of Semenya online. In fact, Semenya is the opposite of hirsute because a lack of male-typical facial & body hair is a telltale, defining feature of the male DSD Semenya has, which is 5-ARD (more on this below).
While some virilization can & does often occur in some females with hyperandrogenism, it's "a relatively uncommon feature of hyperandrogenism, and its presence often suggests an androgen-producing tumor." Virilization to the extent seen in XY people with functioning testes, male levels of T & male sensitivity to T like Semenya has happens rarely, if ever.
https://www.ncbi.nlm.nih.gov/pubmed/16772149
In case anyone is wondering on what basis I can make the claim that Semenya has testes & no ovaries: this was made patently clear in the summary of the Semenya decision released by CAS in early May. It was made clearer still by the IAAF in several plainly-worded additional documents clarifying Semenya's condition released in succeeding weeks.
Now that the full 163-page CAS decision has been released, the facts of Semenya's condition are even clearer. From page 73, point 292 on, the decision shows that the IAAF's position is Semenya has 5-alpha reductase deficiency, aka 5-ARD. This is a disorder or difference of male - & only male - sex development.
The genetics specialists at the NIH in the US describe 5-ARD as "a condition that affects male sexual development before birth and during puberty. People with this condition are genetically male, with one X and one Y chromosome in each cell, and they have male gonads (testes). Their bodies, however, do not produce enough of a hormone called dihydrotestosterone (DHT). DHT has a critical role in male sexual development, and a shortage of this hormone disrupts the formation of the external sex organs before birth.
"Many people with 5-alpha reductase deficiency are born with external genitalia that appear female. In other cases, the external genitalia do not look clearly male or clearly female (sometimes called ambiguous genitalia). Still other affected infants have genitalia that appear predominantly male, often with an unusually small penis (micropenis) and the urethra opening on the underside of the penis (hypospadias).
"During puberty, an increase in the levels of male sex hormones leads to the development of some secondary sex characteristics, such as increased muscle mass, deepening of the voice, development of pubic hair, and a growth spurt. The penis and scrotum (the sac of skin that holds the testes) grow larger. Unlike many men, people with 5-alpha reductase deficiency do not develop much facial or body hair. Most affected individuals are unable to have biological children without assisted reproduction.
"Children with 5-alpha reductase deficiency are often raised as girls. Some of these individuals adopt a male gender role in adolescence or early adulthood, while others adopt a female gender role."
https://ghr.nlm.nih.gov/condition/5-alpha-reductase-deficiency