Retards crossing a river on a raft

I received an email forward from a friend in Perth and it had a Flash game attached to it. It's a game about helping some retards cross a river on a raft.
The retards are a father, a mother, 2 sons, 2 daughters, a thief, and a policeman.
The raft can only fit 2 people at once and there are also many other rules that make the game more challenging and difficult.
One of the rules is; the father cannot be left alone with the daughters and the mother cannot be left alone with the sons.
Erm.... why is that so? If left alone then they will be up to some hanky panky?
Another rule is that the thief cannot be left with the family without the policeman being around. This one makes more sense. But then, the thief can be left alone on one side woh. Won't he run away? He's not even cuffed! He is a stupid thief...
Oh.. and only the policemen, the father and the mother can operate the raft. In other words, the kids and the thief are stupid.

Possibly my friend sent it to me because he couldn't solve it. It's ok man... not all of us are smart. But you have come to the right person.

After you win, you should see the characters raising their arms in the air like monkeys, celebrating that you have successfully helped all of them cross the river.
Download the file.