Speculations of Leonardo's sexuality stirred after he was arrested on the charges of sodomy with a 17 year old male model Jacopo Saltarelli. In 15th century, such acts were prohibited by the conservatives, thus making it a crime. No one supported the case against him and the charges were eventually dropped.
Leonardo never had 'normal' relationships (women), was never married and got zero kids but produced a lot of proteges. One was named 'Salai' which translates to 'offspring of Satan' and true enough, he was most likely an offspring from hell. Salai was generally a pain in the ass but managed to stay with Leo for 20 fucking long years and appeared several times on his sketchbooks. Many theorists believed that the Mona Lisa painting was actually patterned from his assistant on the basis of how 'Mona Lisa' could be rearranged to 'Mon Salai' --- 'my Salai' in French. Too much for a protege, huh? I could only surmised that they could possibly be lovers!
Meanwhile, a lot of conspiracy buffs have stated their own conviction on Leo's real sexuality that he was indeed a homo. Whatever he was, for sure the gay community is more than glad to have him as family!
P.S. LDV is a Renaissance Florentine and the word 'Florenzer' is a German slang for homosexual.