Funnily enough, they evolve, and mostly in Texas, because the Texas school system is such a big buyer of books and the publishers don't want to make many different versions. So the objections of Texas fundamentalists can affect what many, many American children learn at school. Weird, eh?
Here's a story about some of the stuff that they discuss down in Texas:
The Dallas Morning News reported last week that conservative "experts" advising the state of Texas on school curriculum are arguing that the state's social studies and history textbooks are giving "too much attention" to some of U.S. history's most prominent civil rights leaders. David Barton, one of the so-called "experts," claimed Hispanic labor leader César Chávez "lacks the stature, impact and overall contributions of so many others." A colleague on the panel agreed, also singling out Thurgood Marshall for exclusion:
"To have César Chávez listed next to Ben Franklin" – as in the current standards – "is ludicrous," wrote evangelical minister Peter Marshall, one of six experts advising the state as it develops new curriculum standards for social studies classes and textbooks. [...]
Marshall also questioned whether Thurgood Marshall, who argued the landmark case that resulted in school desegregation and was the first black U.S. Supreme Court justice, should be presented to Texas students as an important historical figure. He wrote that the late justice is "not a strong enough example" of such a figure.
Goddess knows what they do about famous women (probably none of them count as famous) or about gender roles and such.