Olympics: Why Algerian Boxer Imane Khelif, Embroiled In Gender Row, Is Being Called 'Biological Male' - Explained

Algerian boxer Imane Khelif's swift defeat of her Italian opponent at the Paris Olympics on Thursday has sparked a row after she was disqualified from a previous competition over reportedly high levels of testosterone. Figures such as far-right Italian Prime Minister Giorgia Meloni quickly condemned that Khelif was allowed to compete at the Games. As the controversy threatened to overshadow the sixth day of the Olympics, here are some facts about testosterone.

What is testosterone? 

Testosterone is a sex hormone produced by both men and women. However men produce up to 20 times more testosterone -- primarily in the testicles.

Women make far less, in the ovaries and adrenal glands.

A normal level of testosterone for men is estimated to be 10 to 35 nanomoles per litre in blood, according to the US Mount Sinai hospital.

For women, it is between 0.5 to 2.4 nmol per litre.

Testosterone levels can also vary widely by age and time of year.

When people naturally produce an excess of sex hormones such as testosterone, it is called hyperandrogenism.

The condition affects an estimated five percent of women, with around 70 percent of cases caused by polycystic ovary syndrome, research has found.

Symptoms include acne, body hair growth and scalp hair loss.

How does this affect sport?

Testosterone can promote bone and muscle mass -- deliberately boosting levels is a common form of doping and is banned.

Research has suggested that people with an excess of testosterone are over-represented in elite sport.

But just how much the hormone boosts performance remains a matter of debate.

The International Olympic Committee's head of human rights Magali Martowicz said in 2021 that there no was no "scientific consensus" on how testosterone