The people who recount the myth of Perseus and Medusa get a large part of it wrong, which was to be expected, because the story was repeated mostly by itinerant story-tellers, who were not above embellishing some of the details. Besides that circumstance, once he became a legendary hero and a king, it seemed not quite right to include all the true facts in the story.
He was born out of wedlock to Princess Danae, the daughter of King Acrisius; that much is correct. One of the king's advisors told the monarch that the boy would kill him some day, so he banished mother and son, thereby earning the everlasting enmity of the little bastard.
This is all common knowledge but the most important fact, one that has almost been lost to posterity, is that Perseus was gay and I don't mean he swung both ways or even that he was just a little gay. During my childhood, I sometimes heard gay men described as being "Queer as a three dollar bill." If somebody back then had applied a similar description to Perseus, he would have been described as being "Queer as a six dollar bill," which, of course, would be twice as queer as a three dollar bill. During my childhood, I was brought up as a proper young lady, so I have never spoken or written the expression, not even as a teenager, because I don't like using slurs such as that, but I used to hear or read it now and then.
At the time, his sexual orientation was known to all, but later story tellers chose to omit it from their tales of him. His gayness was so well known during his youth, his name was sometimes used in referring to a gay man. It still is although the user of the name probably doesn't know the source of the term, and it has been Anglicized to "Percy."
He did slay the Gorgon Medusa. That much is true, and the weapon he used to dispatch her β his sword β and that he chopped off her head are also correct and he brought that beautiful head to King Polydectes, as promised, ostensibly as a wedding present. What is not true is that he looked at her reflection in his shield, which was polished as a mirror, rather than straight at Medusa and thereby was able to nullify her power. In fact, he looked right into the face of the Gorgon and had no problems doing so. He was immune to her beauty, even though it was so incredible it could mesmerize any straight man, rendering her victim unable to fight or flee or do anything else.