for the 5 year old it's actually possible due to genetics and as long as a girl has reached puberty and started ovulating, she can get pregnant.
delivering the baby safely, is one entirely different thing though.
I think situations like this happen all over the world, just that they're unreported.
Education is important! Don't forget that kids! Think about the consequences!
Underage sex isn't a recent phenomenon. It probably already happened thousands of years ago, when life expectancy was really short and people have to reproduce fast before they die.