My 7-year-old is pooping in his pants

My 7-year-old son is pooping in his pants and has been for some time. He has not been abused and lives in a loving 2 parent home. This pooping is almost a daily occurrence and when he does it, he doesn't want us to know he has done it. If we are out somewhere and I smell it, he will deny it to the bitter end which often results in me dragging him to the restroom and cleaning him up while he is hollering because he is still denying there is any poop in his pants. I just don't know what to do to get him to stop. I have tried reward, punishment and doctors to see if something was wrong. Apparently this happens to other parents as I have seen other posts on this subject. Please tell me what's wrong and/or what I'm doing wrong.
Helpless in Louisiana...

[margypops]

could he he behaving like this to get attention?sometimes negative attention is better than none. What interest has he got does his Dad play games with him , when weather is good maybe basket ball or other sports, board games when its raining ..Fun and a connection with you both .Are you sure he isnt just wiping properly , children are not good at it, and its soield their underwear or is it a full poop?

[teddybears4ever2]

Have you had him checked for IBS, chrons/colitis?  Also are there certain foods that he eats that make him do it?  

[amfloyd123]

He is an only child and gets all of our attention. I have not had him checked for Chrons, however, I have taken him to his pediatrician and there appears to be nothing medically wrong. I would think, logically, this is a ploy to get attention, but we are constantly playing with him, reading books, karate, or engaging him with something. He doesn't care whether we are at home, on the soccer field, at karate, or in the grocery store; he will poop in his pants anywhere.