Short answers, pulled from the story.
Ancient Greek texts name King Thestius of Aetolia as her father and Leucippe or Deidameia as her mother. Alcman claimed Glaucus and Laophonte were her parents instead while Eumelus argued for Sisyphus and Panteiduia.
Zeus disguised himself as an injured swan fleeing from an eagle near the river Eurotas to claim protection from a predator. He laid with Leda that same day before she lay with her husband Tyndareus creating children with different fathers.
Athenaeus recorded that one egg held Helen and Pollux while the other contained Clytemtra and Castor. Pollux emerged as immortal because Zeus fathered him directly whereas Castor remained mortal since Tyndareus was his biological parent.
Leonardo da Vinci painted a famous work now lost to history while Michelangelo created another version surviving only through 16th-century copies. Raphael Peter Paul Rubens Salvador Dali Sidney Nolan and Honoré Desmond Sharrer also depicted the scene in their own styles.
William Butler Yeats wrote a Modernist poem titled Leda and the Swan in the early 1900s. Eli Goldstone published Strange Heart Beating in 2017 referencing Yeats' poem directly while Hozier released Swan Upon Leda in October 2022 responding to Supreme Court decisions.