female characters - Is there a generally accepted critical and/or feminist response to Heinlein's work?

I personally enjoy reading Heinlein, but the argument has been made to me that "All of his women are basically men." I have also heard it said that he basically tried to write forward-thinking literature (from a gender-equality perspective) and failed miserably. Can anyone back this up (or refute it)?

Answer

I was searching around for some well-cited academic analysis and/or non-fiction Heinlein might have written that could clarify his intentions and beliefs relevant to feminist criticism and came upon this question. I can't do much more than round out the perspectives on Heinlein's general portrayals (as being mostly positive) with some canonical examples that highlight some of the (arguable) negatives.

I've edited this answer some over the years as I've read more Heinlein and to try to clarify the context of my answer. But I have taken it back to bare bones. This may make it easier to misunderstand, but as some misunderstandings are deliberate, there's little I can really do to prevent that.

Introduction

Despite the claim that "Heinlein's women are basically men," Heinlein repeatedly emphasizes in much of his work that men and women are innately different in the workings of their minds and emotions due to their biological sex. The TL;DR is that, despite a perceptively positive slant, Heinlein frequently depicted differentiation between men and women and reasoning for it "suspiciously similar" to traditional sexism.

Digressing momentarily to my opinion, I don't think the positive aspects of Heinlein's portrayals of women are to be found in either the absence of sexist stereotypes or in deeply nuanced characterization (that wasn't his strong point). Rather, Heinlein's narratives seem to say that many hallmarks of traditional gender roles are due to biology. But the take also seems to be, "So what?! If men can work, invent, govern, and fight under the influence of their hormones, so can women." This is not a bad message.

If that is the message. It's not clear if the gender essentialism in Heinlein's characters and plots comes from a traditionally sexist mindset, or if it was meant to cater to it, or maybe meant to say that different people will naturally have different perspectives and that their sex will influence those perspectives. Meaning is hard to pin down, thus my interest in Heinlein's own takes on his own meaning.

Sexist Memes in Heinlein

The following are canonical examples of "suspicious" portions that could appear to be sexist (and mostly, I think, disprove that "his women are basically men"). There are vague spoilers throughout. The majority cite narration, plot events, or dialog. The last cites a letter Heinlein wrote to a publisher. I haven't read as much of Heinlein's YA; maybe check out Heinlein's Female Troubles, which focuses on his YA.

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  His characters do suggest that sex affects the work women are fit for in less civilized societies--for their own good, of course--and aren't always "proven wrong." (Farnham's Freehold, The Number of the Beast, Time Enough for Love). Traditional sexist memes invoked: "Nature over nurture" and "Women need to be protected."

  
  



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  Also it is clear that, in Heinlein novels, all women are "naturally" inclined to desire children and to nurture them, unless they have been traumatized (Friday, Stranger in a Strange Land, Podkayne of Mars). Traditional sexist meme invoked: "Women are naturally maternal."

  
  


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  He wrote a couple of women who said that women get the most horny when they think about pregnancy and enjoy sex the most when pregnancy is a possibility (To Sail Beyond the Sunset, I Will Fear No Evil). Traditional sexist meme invoked: "Women's sexuality has ulterior motives."

  
  


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  Plot events suggest that women are so overwhelmingly attracted to powerful men that, without regard to their partners' feelings, they will deliberately seek out and nurture cuckoo's eggs if a sufficiently desirable mate appears (To Sail Beyond the Sunset, Time Enough for Love). Traditional sexist memes invoked: "Women will trade up to more powerful caregivers" and "Women are faithless."

  
  


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  Some characters seem to support the notion that the most feminine women are frequently a little vapid--although the justification might be their preoccupation with the very serious matter of creating the next generation (Stranger in a Strange Land, Number of the Beast). Traditional sexist meme invoked: "Women are silly."

  
  


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  Several women narrate that they are smart: smart enough to realize that, as women, it doesn't best serve them to flaunt their intelligence. Instead, they can deliberately let men think they are stupid and benefit from this because the men will do things for them while simultaneously underestimating them (To Sail Beyond the Sunset, Podkayne of Mars, Friday). Traditional sexist memes invoked: "Women are manipulative" and "Women use sex against men."

  
  


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  He writes of much older men who are attracted to barely pubescent girls (and vice versa) and implies via narration that this is very natural on both ends. Compounding this, girls as young as 12 are implied to have sufficient maturity to pursue this choice. How? The girls come back few years older and get laid (The Cat Who Walks Through Walls, To Sail Beyond the Sunset, Time Enough for Love). Traditional sexist memes invoked: "Men are way into young girls, but why shouldn't they be when the young girls pursue them" and "Women mature faster than men."

  
  


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  One novel suggests post-menopause is the best time to seek a career for women (To Sail Beyond the Sunset), since they no longer have better things to do. Traditional sexist meme invoked: "Building a family is the dream for women". Remember, in traditional sexist stereotyping, babies are always the most important thing for women. They are (or, one supposes, should be) important for men too, as members of the human species--but are so much more especially important for women that women can't/shouldn't/won't do anything else.

  
  
  


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  One narrative justifies a character abandoning his wife of many decades--in the process attempting to deprive his children and ex-wife of the vast majority of their communal money and property in favor of his new, young wife and his new stepchildren--on the rationale that he's just doing his duty by his new wife (To Sail Beyond the Sunset). Traditional meme invoked: "The domestic/caregiving role has no value compared to breadwinning."

  
  


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  Some of his female characters judge others who do not conform (especially to the obsession with motherhood), implying that all right-thinking, truly feminine women will sympathize and agree with their perspective--that any who don't are unnatural and unfeminine (To Sail Beyond the Sunset, I Will Fear No Evil). Traditional sexist meme invoked: "Women are catty."

  
  


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  At least one of Heinlein's juveniles, if you take Heinlein's own word in a letter to his editor, may be a parable for mothers who focus too much on their careers and too little on their children (Podkayne of Mars). Unless he was being sarcastic in the letter...dot dot dot. Traditional sexist meme invoked: "Bad mothers are ruining the world."

  
  

Most of these appeared in multiple novels, but they only scratch the surface of Friday and I Will Fear No Evil.

SPOILERS for Friday

There is a notorious rape in Friday. She does literally say that the best option for a rape victim is to try to enjoy it. On the other hand, she indicates that it's more pretending, says she can consider this because she is trained, and that it is a psychological tactic to lower her rapists' guard to aid her escape. On the other other hand, she also mentions finding one of the rapists almost pleasant and later marries him. On the other other other hand, she kicks his ass first and makes him admit to his crime (although OOOOH his apparently genuine remorse is overshadowed by, "you were so sexy I couldn't help it").

END SPOILERS for Friday

SPOILERS for I Will Fear No Evil

There are definitely some creepy overtones and unpleasant implications in the events of I Will Fear No Evil. To wit, an old man's brain gets transplanted into his beautiful young secretary's body: her body is now literally his and yet she's still in it. Her personality lingers in the body with awareness. She cedes control to him, however. Over time, the sex of his body changes how he thinks and feels: he becomes she. In some cases, what would have been offensive to him as a man became acceptable to her as a woman--even being talked down to and sexually harassed.

END SPOILERS for I Will Fear No Evil

On a closely related note, there are also noteworthy things in Heinlein's treatment of LGBTQIA+ characters. For example, he portrays homosensuality positively (Galahad, Mike the Martian), but wrote at least a couple scornful asides about homosexuality. Also, he portrays a certain amount of gender fluidity positively (Mike the Computer, Joanne Eunice, Slipstick Libby), but also seems to say it's dysfunctional if one's behavior doesn't match relatively traditional behavior deemed appropriate for one's sex.

Conclusion

I hope my examples show that Heinlein's work can come off as regressive today for good reasons. Still, I do personally think any writeoff of it as bad for/at women is as inaccurate as any vaunting of it as great for/at women.

As to the man himself, there's no doubt that some of the ideas he explores were ones he agreed with, but it's not clear from the novels alone which ones.