If the universe has any purpose more important than topping the woman you love and making a baby with her hearty help, I’ve never heard of it. - Lazarus Long - Time Enough For Love, Robert A. Heinlein 1973.Lazarus Long was a prick. A prick with an uncommon respect for and admiration of competent women for his time, but as Galahad noted "...he has remained canalized by the primitive culture he was brought up in." Not surprising as Heinlein was canalized by the same primitive culture. Woodie Smith 1912, Heinlein 7/7/7 (1907.) In Christian America where men were men and women were baby breeders. Feminism was on the not to distant horizon, with some closet feminists trying to break the Kinder, Küche, Kirche track for women. But until the mid-20th century and reliable contraception a working mother was of necessity rather than choice and "proper" mothers were expected to stay at home until the youngest child was in Kindergarten which effectively eliminated a career in a well paid profession. The options were volunteer work, teaching and service occupations.
The early feminists tacitly accepted this culture, and advocated non-breeding for professional women. At worst, a long delayed first and generally only child long after becoming established in a career. Women who chose to breed in their 20s and still fight the misogyny of most professions were viewed by feminists as outlyers and not "real feminists." The men who supported their choice of career and parent, were occasionally labled "enablers" of a dysfunctional choice for their wives. Never mind that they too payed the price of parenting in their careers, less than women due to privilege but nevertheless choices had to be made that limited career opportunities. But this mind set still lingers in the feminists who despise Heinlein for writing about women who intend to be mothers among other things.
The problem feminists have with Heinlein women seems to be that all those intelligent, competent women were interested in propagating their genotype and realized that an intelligent, competent man was a necessary adjunct in that endeavor. Since Heinlein men are basically pricks one must appeal to the prick to get the genes.
Make no mistake. According to the prevailing misogynic social ethos of Heinlein's formative years, especially the military ethos, all his male characters are pricks. See The Number of Beast where the pricks are going to go gallivanting around the multiverse while the ladies stay in Safe Harbor to have babies. Even late in his career his basic canalization was that men were gallant protectors of their women, but in general he was able to overcome this and substitute support and partnership for gallantry and most of the families had at least equally competent and frequently more competent women at the head.
Heinlein was raised and socialized in a society where sex meant having babies. (Disclaimer: I was raised in the same social ethos by feminists whose mantra was make damn sure you have sex only with a carefully chosen women who will be a partner in a good family. Recreational sex was not an option.) The difference in his later books was that recreational sex was an option, and the women knew they could manipulate pricks by effective use of recreational sex. But in accord with Heinlein's early socialization he created few male characters that were immune to such manipulation. I can only think of one male protagonist that was comfortable with non-manipulative recreational sex as the line marriage structure depended on it.