Human trafficking is way bigger problem than people understand. Iowa is a major corridor due to the ease of travel - putting ground between you and the authorities quickly and easily. My daughter just graduated in CJ and put me together on this, I was shocked.
As far as self-defense, guns, mace, tasers, et al:
#1 is AWARENESS. Keep your head up, walk confidently, and don't go into the proverbial dark alleys in the first place! Do this and the odds you get in trouble are vanishingly remote.
#2 is physical self-defense, any kind of martial arts at all. Just knowing how to hit someone in the eyes, throat, etc is a big deal, and training to do it so you are able to react and not freeze. And it will help you with #3.
#3 is a weapon. Whatever you prefer, or whatever is handy (keys are great in a pinch). Concerned you won't be able to unholster it or it will be used against you? See #2 above - pop the guy in the eyes, buy some time and space, then use your weapon.
I would STRONGLY encourage you all to have your kids take a class in martial arts or self defense. Boys and girls both, and take yourself along while you're at it. Odds are they will never need it, but it's good exercise anyway, they are usually fun, and it builds real self-confidence like you won't believe. And when you walk around looking confident, you are much less likely to be targeted. Until we live in a perfect world, train your kids to fight back!