The fact that all pilots in the novel are women (in contrast to the infantry, which is entirely male) has been cited as evidence of progressive gender politics within the story, although the idea expressed by Rico that women are the motivation for men to fight in the military is a counter-example to this. A 1996 science fiction encyclopedia said that like much of Heinlein's fiction, "Starship Troopers" exemplified "macho male culture". The prosthetically enhanced soldiers in the novel, all of whom are men, have been described as an example of the "hyper-masculinity" brought on by the proximity of these men to technology. The story portrays the Arachnids as so alien that the only response to them can be war. Feminist scholars have described this reaction as a "conventionally masculinist" one. Steffen Hantke has described the mechanized suits in the novel, which make the wearer resemble a "steel gorilla," as defining masculinity as "something intensely physical, based on animal power, instinct, and aggression". He calls this form of masculinity "all body, so to speak, and no brain". Thus, in Hantke's reading, "Starship Troopers" expresses fears of how masculinity may be preserved in an environment of high technology. This fear is exacerbated by the motifs of pregnancy and birth that Heinlein uses when describing how the soldiers in suits are dropped from spaceships piloted by women. Though Rico says he finds women "marvelous", he shows no desire for sexual activity; the war seems to have subsumed sex in this respect. A 1979 summary argued that despite the gestures towards women's equality, women in the story were still objects, to be protected, and to fight wars over.