I like to eavesdrop on people’s conversations. I considerate it to be one of life’s most interesting (and potentially risky) hobbies. Just this morning I overheard one co-worker say, “Well that’s why you need to have more than one kid; in case one’s a dud!”
I think he makes a very good point. If you’re counting on some care during your elder years, and you only have one child, and that child is a dud; you’re screwed. It really is important to consider the long view when you’re raising children, isn’t it?
Then again, hopefully you’re doing the parenting thing effectively enough that you won’t raise a dud.