The Pope is Pregnant

You are thrown into a prison on an island in the endless sea, surrounded by a magical barrier that you can only enter but not leave.

But at the last moment you are given a mission. A black magician tasks you with keeping the unborn child of a self-proclaimed pope alive after its birth.

As you pass through the barrier and dive into a shallow lake, you notice your faces collapsing and your bones shifting inside, your flesh molding into an androgynous body and your primary sexual characteristics atrophying.

Upon emergence, you realize that you are now sexless like all other prisoners, at least until your first Kemmer, a phase of 10 days in a 30 day cycle. In the Kemmer you form sexual characteristics for the duration of the Kemmer until you shed your gender again.