Dweller couples will reach 100% happiness if they make a baby.

Pairing Dwellers up will notify you if they are of the same bloodline. The game will not allow incestuous relationships. Mix up your mating pairs since anyone in the same bloodline won’t breed with another person in that same bloodline.Try to keep a good ratio of working Dwellers to Kids.

Kids can't work at all, so make sure you don't have more Dwellers than you can feed in your Vault.You will also obtain better weapons over time. It's not worth keeping as you do the same or more damage with the fist. Some can train up SPECIAL stats and others can search the Wasteland. Having a few more Dwellers than can be working for resources at a time can be helpful.It is worth your time to wait at a certain population level and increase Dwellers SPECIAL stats to increase the efficiency of your resource gathering rooms. Don't increase your population too fast.They don't need to hang out in the Living Quarters. Be sure to put pregnant women and their mate back to work in a room once they are done consumating.Give those weapons to other Dwellers that can use them. They will always flee when danger is present, so giving them weapons is pointless. Don't arm pregnant women with any weapons.

Fallout shelter exploring tips