Just for fun
The sims can get drunk, some sims have a trait that requires them to get drunk or have their mood be affected negatively. Alcohol is called mead or ale so the younger ones may not know what it is, but they'll figure it out.
As with all Sims games, Sims can have sex in the bed (it's called woohoo). Unlike other Sims games, any Woohoo can lead to pregnancy. And raising a child is very unrealistic. You feed and rock the baby a little, it grows into a child, and you don't have to talk to it again. You really don't need to talk to your spouse either. Talk to your kids about this so they'll know marriage and kids aren't anything like this.
There is some violence. Your sims can fight with swords or fistfight. They can also jump into a pit to fight with a monster.
It's just for fun, just talk to your kids if it seems like they lost touch with reality.
What other families should know
Too much violence
Too much sex
Too much drinking/drugs/smoking