Why do many adult married children often eat meals at their parents' homes but never return the courtesy by inviting their parents to eat an occasional meal in their homes?

Because they just don't think. Why don't you say "It would be nice to have dinner at your house once in a while." Not a question, just a statement. ===ANOTHER ANSWER=== IT SOUNDS LIKE they are victims of what I have coined "GMS". (GOOD MOTHER SYNDROME) The mother (or parents) give, give, give, never ask for anything in return. This teaches children (unfortunately) that they are entitled to receive and never have to give back. The mother or parents think that by spoon feeding their children and wiping their butts until they die, that somehow they are being "good parents", but actually they never teach their children to grow up and act like adults. Trust me, I've been there, done that. Now I teach families how NOT to do that. It's a hard cycle to break, but it can be done. HOWEVER, the parents have to realize the situation and say point blank that they are not "cash cows", and want something in return. In there lies the dilemma--folks that are "GMS"ish never really realize what they are doing or have done and the cycle continues. I'm sure people see themselves in what I'm writing and swear that "he doesn't mean me!" When enablers (aka GMS) can come to terms with what they expect of their children, and what they have allowed over the years, then, and only then, will adult children either wake up and reciprocate, or in some cases, distance themselves from the situation. That's when they don't "get, get, get," and become distant because their little egos are hurt and think "mom and dad are out of line". The happy ending is the grown children "wake up and smell the coffee" and change their behavior. Then the parents are invited over MORE than they have been INVITED, and realize what being a grown-up is all about. Because they are usually lousy cooks and many of them order in. Pizza, Chinese, etc. Seriously, I live in Canada and many of the young men and women don't know how to cook or even boil water. Parents should always teach both their sons and daughters to cook. My brother is a fantastic cook and so am I, but he beats me hands down when it comes to making good bread. If your children are in their 20s then this is fairly normal. They have been use to eating at "good old mom and dads" for so long they don't think long enough to realize an invite would be nice. If it really bothers you then communicate your feelings towards them and tell them you aren't a fast food chain and would enjoy coming over to their home once in awhile. I'm sure they'll get the message. I remember in my early 20s when I was married to my first husband I did make an effort and had my parents over for dinner. I made a delicious dinner, but when it came to dessert (apple pie/ice cream) my father went to cut it with his fork and it flew across the room! LOL Oooops, I made that pie crust like cement! We all had a good laugh over it. My mother gave me "fail safe" recipes for pie shells and I butchered everyone of them so I buy them now.