Start to Intro

I added the summary component (which briefly touched on gender diagnosticity) as a way to transition to the next part of the introduction - the gender diagnosticity section. However, I am definitely open to it being moved to the end of the introduction as a way of concluding the intro :)

Also, with regards to your comment about the Lippa et al. paper, I personally think it would be best to mention it in the next part of the intro (the gender diagnosticity section) instead of this section.

I personally think a version of the summary that was written could make a nice final to the introduction so we can also lighten this first section. However, if everyone else thinks it should stay that I am also fine with that.