I remember growing up with tales of child brides from the backwoods of Kentucky or out in the Ozark's. The joke was that if you did not behave yourself, you would be married off to cousin Lew. We all laughed about it because child marriages only happened in third-world countries. Heck, we were kids and we knew that.
I recently read a story about a child marriage in Australia. A 12-year-old girl was living with her 26-year-old husband. They were caught when they applied for spousal benefits. To be clear - the marriage happened in Australia and was facilitated by the local Islamic culture and mosque.
I hate to say it, but the problem is both religious and cultural. I think religion, in this case Islam, reinforces the cultural aspects of the problem. Plus, Muslims feel the right to practice their religion by marrying child brides, even though the culture in Australia forbids it. In America, anyone involved would end up in prison, in Australia, I have no feel for how they would handle it. My fear is that Australia will mishandle it and we will start to think of them in third world terms. Immigration and religion caused Australia to regress. How sad is that? I don't know how Australia will fix this mess, but they must.