As background, Heinlein was a socialist in the 30's, while later in life he tended to express libertarian views. His wife Ginny was a biochemist and a navy (WAVES) veteran. There is a story that when he was used on TV as a color commentator during the Apollo program, he flustered Walter ConkiteCronkite by suggesting that women should be allowed to be astronauts. However, his views with respect to feminism and women's roles were certainly not PC by modern standards.
Early career, 1939-1947
Heinlein's fiction from this period shows him still working on putting together his style, with some of his work such as For Us, The Living and Rocket Ship Galileo being noticeably below his later level of proficiency. This period provides the best ammunition for those who want to portray Heinlein as racist and misogynistic.
In 1941, he published two novellas in Astounding, "Universe" and "Common Sense," which were later combined into a fix-up novel called Orphans of the Sky. They depict a society aboard a generation starship that has degenerated into ignorance, superstition, cannibalism, and slavery. Slavery includes all or nearly all women, who are treated as chattels, are named by their men, and are subject to casual physical abuse. (There is one female character, a knife maker, who lives independently and is afforded some respect because her craft is important, but she is beaten down by one of the sympathetic male lead characters when she attempts to stand up to him.) Whereas the other negative aspects of this society are treated very creatively, from multiple angles, and in considerable depth (e.g., a sympathetic character narrowly avoids being eaten), this is not so for its misgyny. Author Amal El-Mohtar writes:
It's often interesting, and competently written, except for the bit where every aspect of this society's ignorance is complicated and problematized and addressed -- except for the women-are-silent-chattel aspect, which up until the very last page of the novel, is taken as read.
Maturing style, 1947-1958
Toward the end of the 1940's, Heinlein broke away from the stereotyped pulp fiction style and became the first science fiction author to sell stories to the "slick" magazines such as the Saturday Evening Post. A big chunk of his early writing during this period was his juvenile novels (1947-1958), many of which were serialized in the Boy Scouts magazine Boy's Life before being published as books. These are written for a nominal audience of teenage boys (although Heinlein prided himself on not talking down to his audience, and fought a running battle with his prudish editor over their contents). In some of these, girls and women are simply absent. One (Podkayne of Mars) has a female lead who is somewhat saintly and has a younger brother who [spoiler 1]
One of the juvenile novels (The Rolling Stones) features a cantankerous, hypercompetent grandmother who is an experienced spaceship pilot. In Starman Jones the teenage female lead hides her intelligence until it is revealed later, and in The Star Beast she sexually manipulates an older man (or tries to?) to humorous effect.
Mature style, 1958-1969
In Heinlein's books for mature audiences from before 1970, we see some of the same shticks, such as the confused or less intelligent man paired with the more experienced and intelligent woman (Glory Road, For Us The Living), and the hypercompetent woman (Glory Road, Barbara in Farnham's Freehold). In Stranger in a Strange Land, the protagonist manipulates his own sexual biology to give himself an androgynous body. In another of his works from this period, when he was at the peak of his powers, the computer in The Moon is a Harsh Mistress consciously switches back and forth between being psychologically male and female.
Late works