Word of warning. I’m going to discourse both on the book and on the Verhoeven’s movie.
He didn't include them as "grunts" probably because the training was sufficiently hard that most wouldn't have made it. If you read the description of the training it wasn't just 12 weeks square-bashing, it reads far more like Special Forces.
It might also have been because he was paying lip service to a society kind of modelled on 50s America where the ladies were the home-makers and females in the frontline weren't even on the radar.
However, having said that, we have the fabulous line about females in high rank and esteem:
"If the Almighty ever needs a hand to run the universe: hot ship pilot Yvette Deladrier" after Starship commander Deladrier brakes her ship's orbit to recover a lander that has blasted off late and which otherwise would miss rendezvous and all on board would perish. I’ve heard from a lot of my friends saying the movie version is utter shit. I’m not so sure. The thing is, Verhoeven was a master of taking existing texts and subtly pushing them into satire by overdoing Hollywood/MTV filming tropes. The viewer was encouraged to look at the films as broad entertainment and then ask what the actions of the heroes had to do with American culture. He did the same with Joe Eszterhas's scripts for “Basic Instinct” and “Showgirls”. “Basic Instinct” is a detective story where the 'hero' is someone who's already gotten away with murder because of his badge, and who shoots another innocent victim before the film is out, while the 'villain' is never actually shown to kill anyone. She's chiefly a suspect because of her sexuality (which is why GLAAD picketed the film) and lack of shame about it. “Showgirls” meanwhile depicts a vision of Las Vegas as a patriarchal dystopia where every woman is judged on her body and literally every male character is a predator of some kind.
If you're into SF, read on.