I have replaced the wax seal (new toilet) several times along with two plumbers and the toilet still leaks at the base.

Does the toilet base start leaking a few seconds after a flush or does it leak when it's flushing? I have a hunch the problem won't be found in the toilet or the wax seal. Back to you, Tom

Best I can tell is after but not sure. You think it is coming back up the sewer pipe after it is flushed?

You think it is coming back up the sewer pipe after it is flushed?
Pretty sharp there guy! You got what I was thinking before I could post it. While wax seals are designed to contain water going down past then the are not designed to contain standing water caused by a partial blockage. I'm supprised that your plumbers didn't fix on this the second time it leaked.
I think you have a partial blockage that should be snaked, Any bubbles or gurgles when you flush? Back to you, Tom

No, the water just goes down. Sometimes it takes 2 or 3 flushes before you can visably see water leaking out from under the bowl. The toilet is currently on the floor I will pour water down the sewer pipe and see what is does and repost later today...

I poured 8 quarts of water down ( 2 4 qrt pitchers) down fast and it did not back up.

OK! Now let's look at the flange. Is it level and not cocked> What material is it?
Have you tried a wax seal with a built in funnel to get the flush past the floor line? Let me know. Back to you, Tom

It is plastic, level and looks to be in good condition. I have tried a basic single, 2 on top of each other, the extra thick ones both with and without being reinforced, the ones with the funnel and some if the other types of seals.

Then you have installed a funnel seal? Is so and it still leaks my next step would be to pull the toilet and snake the drain line. Good luck, Tiom

Dnewman,
Bowl waxes should never be stacked. A toilet, installed on a correctly mounted closet flange ( the flange should sit atop the floor ), should sit leak proof, and odor free for decades. Stacked gaskets are prone to shrinkage, failure due too probing by a closet auger, and, erosion from continuous contact with running water.
A bowl wax should never come in contact with water unless the piping the toilet is connected to becomes blocked, and, even under that circumstance, a single bowl wax can withstand the very slight pressure ( about 1 /2 lb ) imparted upon it by an overflowing bowl.

Attempting to use multiple gaskets usually means there is a depression adjacent to the flange. This area will collect moisture, and, if there is wood, or other pourous material present, mold and rot will develop... ]

The floor in new there is no depression.

Well, I bought a new el-cheapo toilet at Home depot ($22) and guess what no more leaks! I could mot see any cracks in the Glacial bay (new also) one but there must have been one somewhere,

Thank you for the update. I would be most interested in learning what went wrong with the old bowl. Good luck, Tom