It may have gone around that you can get children from two units... but spoilers still remain on how, who, and so forth...
Children characters are unique in their own sense as they are kind-of customizable (though, less than your character) by whoever happens to be both parents (Those who have a support rank S with each other).
Even their appearance slightly depends on who one of the parents are (except for Lucina, who's been seen since Chapter 1), have their stats altered on the strengths and weaknesses of the "other parent", and even know some skills that the parents already knew.
Oh, and I said "other parent" before because each child only comes with a specific character who they look/dress/act like. (Chrom>Lucina, Your Character>Morgan), and the other parent mostly determines the changes.
Any of the children you guys like? I like Morgan since, like your own character, she can become most of the classes in the game (even tactician), so you really get a choice with here unlike the others. (I've only really recruited 3 children, though... out of possibly many more.)
Now how are they here...?
Even their appearance slightly depends on who one of the parents are (except for Lucina, who's been seen since Chapter 1), have their stats altered on the strengths and weaknesses of the "other parent", and even know some skills that the parents already knew.
Oh, and I said "other parent" before because each child only comes with a specific character who they look/dress/act like. (Chrom>Lucina, Your Character>Morgan), and the other parent mostly determines the changes.
Any of the children you guys like? I like Morgan since, like your own character, she can become most of the classes in the game (even tactician), so you really get a choice with here unlike the others. (I've only really recruited 3 children, though... out of possibly many more.)
Now how are they here...?
They came from the future 
