What is the Correct Resolution of the Twin Paradox if Any?

In discussions with theoretical physicists I have met the following "resolutions" of the twin paradox of special relativity SR as the paradox/apparent contradiction of different ageing of two twins, one staying at home and the other traveling on a round-trip (showing to be younger at return):

1. The different ageing shown in SR is real physics and can be explained within SR.
2. SR says nothing about the physics of ageing due to round-trip travel and so there is no twin paradox to resolve.
3. The different ageing shown by SR is real but can only be explained by the general theory of relativity.  

Since 1.-3. are contradictory, I have asked a panel of theoretical physicists about the correct resolution, and will report the answers, when received. You are also welcome to submit your own resolution as a contribution to the discussion.

My question is the same as posed in an Open Letter signed by 142 physicists and others directed to the physics community, which received a very vague response. Read and contemplate! You will find clear evidence that there is no commonly accepted resolution, only resolutions which are viewed to be incorrect by parts of the community.

It reminds about the explanation of flight, for which the aerodynamics community only offers a number of different contradictory versions listed on e.g the NASA website as all incorrect, but no explanation claimed to be physically correct. For a physically correct explanation, see The Secret of Flight.

My experience so far (which is the same as that recorded in the Open Letter) is that leading physicists  are not on request willing/able to present a resolution of the twin paradox. What you get is:

• There is no paradox, because SR is free of paradoxes. 
• The paradox was solved very long ago in some way which no longer has any interest. 
• Take a look at what wikipedia says. 
• It can easily be solved within SR by using simple space-time diagrams. 
• A resolution can be found by invoking general relativity, but that is so complicated that details cannot be given. 
• The twin paradox is of interest only to crackpots, not to professional theoretical physicists who have many much more urgent questions to tackle.  

What you don't get is anything claimed to be a correct solution accepted as such by the theoretical physics community. This is more than 100 years after the paradox was formulated.  If you think that what I say cannot be true, try out by asking the question yourself to your physics teacher or college. 

The only way out in this hopeless situation is to opt for the "no paradox" version insisting that SR is logically consistent and as such free of paradoxes and beyond reach for physical paradoxes. But this would mean that SR is not a theory about some physics, which can (appear to) be paradoxical or be false, only a mathematical theory identical to the Lorentz coordinate transformation. The effect of such a step would be far-reaching, since modern physics is based on SR, and if SR is empty of physics that would make a lot of modern physics empty as well. So this way out is not possible...

PS If you repeat your question, because you don't get any reasonable answer, then you are met with anger and frustration, which is understandable if not very pleasant, or simply silence.