Is this unfair? The IOC has moved to bar transgender women from competing in women's categories at the Olympics. Some have praised the decision, while others say it is not backed up by science.
Trans women banned from women’s Olympics
Weight of the world: Just five years ago, Hubbard made history at the Tokyo 2020 Olympics. Glossary
Transgender - Someone whose gender identity (what they feel inside) does not match the gender identity they were assigned at birth (based on their biology).
Cisgender - A person whose gender identity matches their sex assigned at birth. The term was first used in academic articles in the 1990s.
Eligibility - Meeting the necessary conditions or requirements to take part in something.
White House - The official residence of the US president, in Washington DC. Burnt by British troops in 1814, it was rebuilt and painted white to hide the smoke stains.
Congenital - Existing from birth. Often refers to medical conditions and anomalies that developed before a baby was born.
Chromosomes - A threadlike structure found in the nucleus of most living cells, carry genetic information in the form of genes.
Caster Semenya - A South African runner with an intersex condition, although she prefers to describe herself as "a different kind of woman".
Testosterone - The hormone that causes people to develop male sexual characteristics. Women also produce some testosterone.
Patriarchal - A society in which adult men have a monopoly on power. In these societies, men tend to hold all political positions, and women and children are also expected to obey the men in their families.