I'm leaning towards 70% chance of a daughter and 30% chance of a son.
Regardless, Angelica's future half-human half-demon half-sibling will be a very interesting addition to the family.
I just hope she keeps the crown princess role though, someone being both Demon Lord and Hero in the future is pretty damn interesting.
Else, we're just gonna have future "I'm the Hero and my younger half-sibling is the Demon Lord!" which is still interesting, although not as fun to me.