I think there are many things that aren't understood. But IMHO, the ONE thing that couples with children don't understand about couples WITHOUT, is that not all couples who don't have children-are childless BY CHOICE. For many couples who are childless, the childlesness is NOT by choice and they are reminded of one of life's cruelties EVERYDAY of their lives and another utterance, by a thoughtless gifted person, makes them just that; more THOUGHTLESS. Each soccer season, each birthday or PTA.
My husband and I desperately wanted, KNEW that we were to have children. But, when that wasn't to be, that IN ITSELF was pain enough.
For some reason, I am deemed insensitve if I don't remember every birthday, but there is never interest in what I do FOR A LIVING. Sounds like a mildly double standard at work.
Barring a 'tit for tat' and who's keeping score, mentality there are riches to be gained from my way of life, though there are days that you'd find me hard-pressed to admit it!!
The world would be a very dull place if we all operated under the same set of circucmstances, but I and others that I know have been relegated to the second-class citizen status for too long.