His anatomical drawings naturally include the sexual organs of both genders, but those of the male exhibit much more extensive attention.
Finally, Leonardo surrounded himself with beautiful young male assistants, such as Salai and Melzi.
Today it is still a topic of Don't ask, don't tell, or the relationship is completely looked over. During Leonardo's life time critics said Salai's work looked like Leonardo's work. Leonardo was said to have seen Salai drawing in a field and then approached his father to train Salai as his assistant and apprentice.
No definite proof exists of Leonardo's homosexuality, there are plenty of indications, in his male erotic drawings as well as in his writings, that he was attracted to males.In his liberality, he welcomed and gave food to any friend, rich or poor." His kindness, his sweet nature, his eloquence ("his speech could bend in any direction the most obdurate of wills") his regal magnanimity, his sense of humor, his love of wild creatures, his "terrible strength in argument, sustained by intelligence and memory," the subtlety of his mind "which never ceased to devise inventions," his aptitude for mathematics, science, music, poetry.What's more, Leonardo was a man of "physical beauty beyond compare." In 1466, at the age of fourteen, Leonardo was apprenticed to the artist Andrea di Cione, known as Verrocchio whose workshop was "one of the finest in Florence".It is said the portrait was hung along side of the more famous Mona Lisa in Leonardo's bedroom in France.Salai as Saint John the Baptist is perhaps most famous for the enigmatic look and smile on Salai's face.
Several things indicate that Leonardo was probably gay.