Now why do you suppose that an extremely athletic, apparently above-average healthy, strong enough to birth several children, early middle-aged adult with absolutely no public record of any health problems of any kind would
refuse to release her medical records?
It's because her daughter Bristol is the mother of the infant that Palin is trying to pass off as her own child.
Sarah Palin isn't known for being smart, just ruthless. When they hatched this scheme, the Palins didn't know she'd be in the national spotlight in a very short period of time. And they sure didn't expect Bristol would get pregnant again, almost immediately after giving birth to her first child. What Sarah Palin has done -- pretending her grandchild is actually her child -- is standard operating procedure for generations of countless mothers of wild-child unwed mothers in small towns everywhere.
Only this time, what happened in Wasilla didn't stay in Wasilla. And she can't admit it now without adding to her reputation as a liar, adding to the hypocrisy of her stance on abstinence-only education, adding to the charges that if she can't run her family then how can she run the country, adding to the belief that she shows one face to the world while using deceipt and secrecy to keep the facts about her true life hidden from public view.
They had no choice but to deny the release of her medical records. But, by doing so, they've confirmed what everyone knew all along. Being evil is one thing, but being incompetent at being evil is pretty bad. If you can't even be good at being evil, what good are you?