If we could marry one of the NPC's that we have rescued and then start a family. To start you would discover special items that you can use as gifts which would increase an NPC's affection toward you eventually allowing you to marry them and then proceed to begin a family. Bringing home pets that you can give to your kids, which they could train and eventually have fun battles with you (going with the pokemon aspect), or just use them "guard dogs" type of deal. Maybe having your wife and children carry out certain jobs while you're away on quests or just exploring. Every once in a while you could be given a gift from your children, something that they may have found or made while they were out of the house, which can be used to display on the spaceship or in your house.