Futaba-kun Change!

Futaba-kun Change! (ふたば君チェンジ, Futaba-kun Chenji) is a manga series written and illustrated by Hiroshi Aro. In Japan, the manga began serialization in the December 1990 issue of the Shueisha magazine Monthly Shōnen Jump. It switched to the sister publication Monthly Shōnen Jump Original in 1993 and ended in the March 1997 issue. A total of eight tankōbon collecting the chapters were released by Shueisha between 1991 and 1997, but it is now out of print. Futaba-kun Change was licensed by Studio Ironcat in the United States, but as the company went out of business their release is also out of print.

Plot
Futaba Shimeru is a normal high-schooler living a normal life, active in his school's wrestling club and slowly getting closer to his awkward love interest, Misaki. This fails to last as he discovers his family's hereditary genetic defect that becomes active at adolescence. Although it will eventually become controllable, either excitement or stress now makes Futaba switch sex. Hilarity ensues. The general status quo of the storyline, tone and atmosphere is maintained until volume 6, at which point Misaki discovers Futaba's secret.

In volume 8, the manga abruptly changes from light comedy to serious science fiction. Futaba, Misaki and Kurin are taken by aliens that explain that the Shimeru family are not merely bizarrely mutated but descendants of a space crash 12 to 13 thousand years ago. They are taken to the star system they originated from to see a structure much like a Dyson sphere, but see that the entire race has been annihilated. Determined to find a less tragic future, they return to Earth. 8 years have passed, all their friends and family have happy lives (Motomura and Nigiri have gotten married and Futana is a celebrity playboy), the Shimeru clan have spread throughout the world, and their condition is now widely known and accepted.