First and foremost, I'd point you at Spider Robinson's essay on the matter in Requiem.
Then I'd suggest that you read Podkayne of Mars or "Poor Daddy" or "The Bulletin Board".
Heinlein's female characters pick their own life paths and often choose to have both family and careers. They have aspirations to accomplish things in life and better themselves, they pursue education throughout their lives and work hard to fulfill the obligations that they have voluntarily assumed in life.
What was the problem again?
Now let's take
"All of his women are basically men."
Heinlein's works are full of smart, capable, empathetic, independent, strong willed women who are often wise and always know what they want and don't let men (or other women, for that matter) deter them from striving after those goals.
So, if someone complaining about this says that these traits make the female characters "men", then ... doesn't that amount to claiming that these are traits that are primarily masculine? Are you sure that this is a "feminist" position?
And if that is not the complaint, then has the author not portrayed women as having as many of the best qualities of humanity as his male characters?
Who's supposed to be the misogynist here, again?
Lets name some of these characters, shall we
- Podkayne Fries in Podkayne of Mars (protagonist)
- Hilde Burroughs & Deety Carter in The Number of the Beast (co-protagonist and both Ph.Ds)
- Maureen Johnson in To Sail Beyond the Sunset (protagonist, Ph.D.)
- Margerethe Graham in Job
- Sadie Lipschitz AKA Hazel in * The Cat Who Walks Through Walls*
- Friday Jones in Friday (protagonist)
- Ishtar in Time Enough for Love (Administrator of the Howard Clinic on Secondus and a clinical therapist)
- Barbara Farnham nee Well in *Farnham's Freehold
- All the female characters in Tunnel in the Sky and in The Moon is a Harsh Mistress
and on and on, I'd have to dig through my pile to find all the names.
I should note that Heinlein's female characters are rarely typical, but then neither are his male characters. Instead they tend to be unusually intelligent, highly educated (either formally or by voracious reading), broadly or deeply accomplished (or both), able to distinguish facts from guess and from wishes, and able to do what needs doing for the duration of the emergency.
I'd sure like to live up to that standard.