Tell those men with horses for hearts

Presidential aspirant Carly Fiorina nominates equoidequine role model:

Secretariat also had what’s called the “x-factor,” a gene located on the X-chromosome that causes an unusually large heart.* Fiorina says she identifies with this. “It’s about the size of his figurative heart, too.” **

Q: What is the difference between Fiorina and a horse?

A: Incitatus did make it into the Senate.

* The "X-linked mutation" theory seems to be an article of faith among a small circle of horseflesh enthusiasts, largely unsupported by evidence. No gene has been identified and no-one is looking for one.

** Secretariat's "figurative heart"? I can't even.