I played through the story of this game in a few days. The game isn't fully complete yet, though. You get to 100% by buying all of the places and doing all of the activities.
The story is very, very fun and I really enjoyed it. A few of the missions involve "shady deals", and some involve prostitution. In one mission you have to go into a strip club to interrogate a man, and some of the rooms are full of sex toys. In a set of side activities, two people have sex in the back of you're car. You don't see anything, but you can hear it.
There are also a lot of mature humor. It's insanely funny, but you'd need to be more on the sexually educated side to find this game fully humorous. But let's be real, all of today's teens will get it.
You can make you're (fully customizable) character naked. The nooks and crannies are all blurred out, though. There are some naked statues scattered throughout the city of Steelport, and you can get a tattoo of a nude she-devil but nothing is really that detailed.
There is only one accessible strip club, and there's no full nudity or any sexual acts.
The characters can have inappropriate taunts or swear when they crash their cars, but it's nothing everyone doesn't hear every day. The worst thing they say is the "F" bomb.
I know that by what you've heard so far, you think this is a terrible game, but it's really not that bad, and you don't have to play the campaign if you don't want your child to. The violence is heavy, but if you fully trust your child it's a great game.