@Nerex
He can't get pegnant because he changes back to a boy everyday. Ovums need to mature some days before be ready to be fertilized
@Elon-chan
The first time that we see "her", she is wearing dress outside, and because this begun when he was in second grade I'm sure he was raised like a...
about getting pregnant, the ovum needs to mature a little first before getting pregnant, and if he is changing sex everyday, the ovum never has the time for that
@starburst98
she still knows the identity of the other girl, that is the whole point of the series, even if the baby wasn't theirs, they wouldn't be relatives
Im sure that in this kind of stories the wife is a normal woman that posess the body of the little sister, making that a comedy were the guy is disturbed by that thing