Not the yolk alone, why would that make a difference? Do the whites tend to contain something people don't react well too?
Yes
1. yolks are easy to digest especially if they are still runny, its like 30 minutes until the body makes use of it
2. whole cooked egg and only egg white take like 8 hours to digest
3. avidin in egg whites which binds some or a lot of biotin depending on how cooked they were, the harder the less active avidin (mostly a problem when consuming raw egg(whites), raw egg yolk is fine).
4. the whites seams to be more allergenic as the yolks, so people might tolerate yolks but not whites
also most nutrition is in the yolk, and majority of the protein. people think the egg whites is where the proteins are, thats not correct, most protein is in the yolk , as is everything else.
i sometimes get problems from eating whole eggs, digestion. you need a lot of stomach acid to get those proteins down. i can easy it with vinegar, or i just eat the yolks, no problem here.
what i do is boil them so that the white is completely hard, and the yolk is a soft ball. when i chew it it melts. also its easy to extract the yolk, i can just peel off the whites around it.
you might offer the cooked egg whites to some animals.
you can also eat the yolk raw, one way to do it, is open the egg and give it into a half full glas of water, now you can fish the yolk out with a tablespoon and eat it.
it might not be possible to separate the whites perfectly from the yolk though. so if a person is really sensitive to the white, its better to cook it and separate it later.
before eating eggs always make the float test, if it floats up its bad. if it stands up but stays low, i would not eat it raw but cook it, if it lies on the ground like a stone its good and fresh, you might eat it raw.
(remember, only dead fish are on the top of the water stream)
also put it shortly under the water beam, that might reveal cracks. if it has minor visible hair line like cracks, do not consume it raw.
i would also do this test in general with eggs even if you hard boil them.