Are Midgets real? (people under the height of 4'9")
Are Giants real? (people over the height of 6'6"). YES and YES. How
Little People and Giants People both exist. Both are Human, Both are most likely born from a normal size human. But Both are HUMAN. Average human Height is between 5 and 6 feet. So according to your theory of 12 and 13 inch penises not existing. You must also be saying 7 and 8 feet tall people do not exist.
This argument is a huge non-sequitur. The two sets of data (normal distribution and extremes in height and in penis size) are unrelated. Even if you knew the normal distribution of each characteristic you couldn't draw the conclusion you have. You might as well say that because unusually tall people exist there must be a number of people with three noses somewhere.
You are entitled to your theory of 12 and 13 inch penises not existing.
I will now take the other end, I don't really believe this but Penis's smaller than 5 inches must not exist!!! If a penis cannot get to big, a penis then most certianly cannot get to small either? Does this sound about right as far as theories go?
No. Again it's a total non-sequitur - i.e your conclusion (that a penis cannot get too small) is completely unrelated to your premise (that a penis cannot get too big). The truth of your statement depends on having evidence of the recorded distribution of Penis size, which you haven't produced.
Every single survey I have ever seen shows no evidence of some of the outlandish penis sizes some on here claim they have routinely seen. I have only ever seen one single survey that saw a solitary individual of 13 inches, but IIRC this was done decades ago (it might even have been in the nineteenth century) and the evidence wasn't subject to independent scrutiny.