Title : Hen Vol 1
Author : Hiroya Oku
Hen story 1
in this story Toriai has sex with a strange
woman and becomes a woman
He finds out it's because of a disease and
that to change back he just heave to have sex with a man.
But he decides to have a litle fun in his new
female form and ends up pregnant and
stuck in this form.

Title : Hen Vol 3
Author : Hiroya Oku
Hen story 2
This story is independent from the story we had in Hen Vol.1 although the main caracther is the same.
Toriai has sex with a woman and becomes a woman
He finds out it's because of a disease and that to change back he just heave to have sex with a man.
But things get a lot more complicated when Nagasaki then Omoto get involved..