It really doesn’t matter whether the desire to lend a hand to a young person in need comes from. Maybe it’s a sense of duty. Maybe it’s rooted in your faith or belief system. Maybe you just want to pay it forward. Foster families, and we know successful ones, are a vital, loving part of the societal puzzle. 
But we also know of those who are less successful. Any time a young person is introduced into a family bringing a difficult past, with possible unknown issues, with understandable neediness— the potential for things to go awry is certainly there.