Is the topic Blended Families and children too narrow or broad to research

Too broad

So how can I narrow it down to perhaps

Blended Families and the family structure

I don't understand the difference. Blended families and family structure seems broader than your original topic.

so how exactly can I narrow it

blended families and affect on children health

Yes, that would be good.

Or how about various ways children cope in blended families.

okay sounds good, then I have to utilize articles to critique it