I hear anecdotally that 20% of the population do not have offspring. I have no idea how factual that information is, but it is certainly much rarer than that within mormonism. So yeah, 20% are probably nonplussed by that, minus a fraction who are childless not by choice.
I've never heard much about Mitt and Ann's children, just how they "struggled" to accomplish their early life. But I hear a bit more about the Obamas' children, and I appreciate Michelle's work with school programs. I don't hear of any similar involvement from Ann, but I do hear about her taste in clothes frequently. ;)