It was a throwaway line in this fic (http://www.fanfiction.net/s/7959874/1/Sulu-You-Fool), About Uhura and Spock breaking up because Uhura wasn't ready to settle down. The pigment skin fic just flashed at me for a second, but the fics are nothing alike :)

^That fic is a sequel to this fic (http://www.fanfiction.net/s/6850849/1/So-This-Isn-t-an-April-Fool-s-Day-Joke)