I've come across a ton of bullshit in my time, some of it from actual doctors, that it's a good idea to catch stuff while you're still young. Let's have chicken pox parties, etc. Let your kids crawl around on the kitchen floor and eat scraps of dropped two-day-old cream cake. That sort of thing. Toughen up your immune system. Stuff like that.

Well I don't think it's ever a great idea to catch any disease. Why would you ever want you/your kids to be sick?