Hi! I'm new to the forum so I'm sorry if I'm posting this in the wrong places but it SEEMS to be the most appropriate section; plus a quick search revealed no threads already made about it aside from reviewing and lyrics, plus that's 4-6 years ago, apparently.
Kasimasi: Girl Meets Girl, by Nobuaki Nakanishi and Studio Hibari, is about the story of an effeminate boy named Hazumu Osaragi who - after being rejected by a girl he loved - was KIDNAPPED by ALIENS who crash landed SPECIFICALLY on the spot where he was standing, which happened to be at the top of a mountain. The aliens were kind though, and rebuilt his body, except that it wasn't his body, but rather a female version. Coming back after being rescued by his/her friends, Hazumu learns to live as a girl, although still coping with being denied his love - although the girl he liked secretly liked him back, but not as a man. Hazumu's long time friend, Tomori Kurusu, is also secretly having feelings for Hazumu. Love triangles ensue!
I've only gotten to episode 8 (out of 12) but I can definitely say this is one of the series with more staying power. It has wonderfully deep atmosphere, and constantly challenges the way the characters (or the viewers) may think about things and how they've changed / how they've stayed the same. It's a story about conflicting emotions and insecurities throughout varied personalities that crosses the borders of gender and doesn't hold anything back.