This lesson should be taught after you have explained what a blog is. It will also have helped to have discussed audience. You will need access to computers.
This was one in a series of lessons I taught where students "travelled" around the world and looked at issues in particular countries. At the end of each lessons, there is a statement with points for and against. At the end of the term, the students chose the statement they found most "interesting" and wrote an piece explaining their position. You could set this as homework instead. LGBTQ was requested as a topic by my class, so this is more about feeding their interest and practising skills than teaching new ones.
If you feel there are key personalities or events that should be covered, please comment and I will edit. Thank you.