Almost 5 year old son has never pooped in toilet

[Momof2inOhio1974]

Hello, we are at our wits end and don't know where to turn (so I am greatful that I found this forum).  Our son will be 5 in September and he has never pooped on the toilet.  He won't even sit on the toilet.  He doesn't say he is scared or anything like that, he just says I don't want to.  We still buy pull ups because if we don't he will hold it until he has accidents in his underwear.  He will have the accidents over and over and hide his underwear behind the couch, in his closet etc.  We taught him to pee standing up, and he never really "sat" to pee.  He has been "pee" potty trained since he was 2.5 years old.  This is getting so frustrating, embarassing, etc. and no one has provided us any advise that has worked.  We try rewards, taking stuff away, threatening etc.  He just has no interest in going anywhere except in a pull up.  He has also been having some learning difficulties as well, but not sure that could be related to the toilet training issue (just behind others of his same age with letter and number recognition etc.) but we have been told there is nothing we can do for that until he gets into the public school system and they can test him (Kindergarten).  Our 11 year old is gifted (we found out when she was in 2nd grade), so this is very hard not to compare them.  She never had issues like this with the toilet and our pediatrician has been no help at all.
Any advice is very much appreciated

[AnnieBrooke]

I disagree with the tough-love concept applied to potty training, since you risk him getting encopresis and getting a disfunctional bowel entirely.  Have you read up on encopresis and talked to a pediatric gastroenterologist?  A lot of pediatricians are simply no help on this issue.

[margypops]

Its time to get tough, you have to remove the pullups they are enabling the problem and allow the accidents .Sounds like he has become anxious about the issue hence the hiding, I also suggest less talk about it.Get him big boy underwear and less words ,no coaxing ,be matter of fact and firm ., no rewards no  threats it makes the situation worse and creates anxiety .If he doesnt want to go anywhere thats okay . If you think he has learning difficulties speak to your Doctor and Teacher . Comparing may not help either .so be casual about it all, dont make any issue ...no pullups and no words...