In a word, it's misogyny. They actually hate women.
So you're scratching you head, thinking, "How can they hate women when they so strongly promote Sarah Palin and Michelle Bachmann?" If you examine these two candidates, you'll see how they embody exactly how little Republicans value women.
They think women should be eye candy. Think trophy wives. Young, attractive, good slim figures with lots of bust on top, even features, good hair. It's all about appearance. That's all we're good for: showing off to the next guy so you can imagine his erection while he's drooling over your wife, your status symbol.
That's all they expect of us women, so they don't pick for intelligence, spunk, character, experience, talent, education, ideas. And if you look at Sarah Palin or Michelle Bachmann, it shows. They pick exactly what they think women should be and are.
And if you get old, or get sick, the Newt Gingriches of the world will cast you off for the newer, younger, prettier, healthier version of eye candy to parade on their arm. She won't be any smarter, more talented, or have any other wonderful qualities either.