'The Virgin and Child with St. Anne'
This is my favorite Leonardo painting - mostly because of the way he has painted Saint Anne (the Virgin Mary's mother - at top). It may have been begun as early as 1500 and it remained unfinished at his death. It is now in the Louvre.
This painting was at the center of Freud's analysis of Leonardo's repressed homosexuality.
Freud had read of Leonardo's childhood memory in which a vulture enters his cradle and flutters its tail in his mouth. This, Freud asserts, "corresponds to the idea of an act of fellatio" and is a "passive homosexual phantasy." He then gets distracted by wondering why Leonardo's mother was replaced by a vulture but, fortuitously, he finds the vulture in the robe of the Virgin in this painting! No, I can't see it either.
From there he goes on to argue that Leonardo was born "illegitimate" and was a "vulture child" because he was raised not by his father and stepmother but by his "poor forsaken real mother."
Below is the preparatory drawing he made which is now in the National Gallery, London. Again it is St. Anne who draws in the viewer and it was much seen and much discussed when Leonardo first placed it on display in Florence.