In it, a grandfather scolds his daughter for kicking his gay grandson out of the house after the boy decided to come out.
The letter was posted to a pro same-sex marriage Facebook page.
The unidentified grandfather says quote, "He was born this way and didn't choose it more than he being left-handed. You, however, have made a choice of being hurtful, narrow-minded and backward."
It goes on to say, "So while we are in the business of disowning children, I think I'll take this moment to say goodbye to you. I now have a fabulous? grandson to raise."