Gendergap v gender gap 

Re this edit  I personally don't have a strong feeling one way or another, though I do tend to like things standardized. FWIW: WP:GGTF is the "Gender gap task force" and at meta, it's Gender gap. I'm pinging , since I believe she was the one to organize, create the GGTF. Again, I don't have a strong preference one way or another.