but wouldn't "tien" be in reference to who it belongs to? And not the children?
1) Mon, mes, ma, les miens, les tiens, etc, agree with the object, not the owner. That means that you always say "mon père", because fathers are always masculine, even if the child is a daughter. So no, it's not a reference to who it belongs to, and never is in French.
2) Enfants is usually masculine. You can use it in feminine, but it's rare. That means that even if they are daughters, you would still usually say "tiens" in masculine. Similarly, you would say (even though it doesn't make much sense... bear with me) "Ces personnes sont les tiennes" would use the feminine form - tiennes - even if the people in question are male, because "personne" il always feminine.
I hope I'm making sense :)
Thanks, you make perfect sense. I typed tiennes by mistake, but this left me to ponder if it was possible to use "tiennes" if the sentence involved girl children. You answered my question and the "personne" example was very helpful.
Why is "Are these boys yours?" a correct translation? Can "enfant" be used to mean "boy" as well as "child"?
Meh. Enfants does not tell if there are only boys or girls or both. So I'd say that "Enfants" should only be translated as "Children".
"Enfant" is always a masculin noun despite the sex of the actual people, just as "personne" is always feminin.... you need to agree with the noun, yes?
No. If you want to invert the subject, you need to add a pronoun. You don't invert regular nouns. So "Ces enfants sont-ils les tiens" is grammatically correct for instance.