there are a lot of conflicts that displace large populations including kids. also natural disasters render a lot of people, including kids, homeless.
what you need to be concerned about is that there are unscrupulous people who pay poor family for kids, either promising they will look after them in the meantime by giving them employment, etc. then they turn around and sell them through "adoption" agencies.
this is why many countries have very strict guidelines and legislations on adoptions.