Unfortunately, Lukacs says nothing in "History and Class Consciousness" about what happens to sex once the identical subject-object of history comes onto the world stage. Will it be better?
Although Lukacs is quiet on this subject he does point out how awful the reified view of sex can be, and as an example he quotes Kant's comments about marriage:
"Sexual community", says Kant, "is the reciprocal use made by one person of the sexual organs and faculties of another . . . marriage ... is the union of two people of different sexes with a view to the mutual possession of each other's sexual attributes for' the duration of their lives."
Here is the reified fragmentation of the subject (the person signing the marriage contract and claiming possession of various kinds of property) and the object (the body). Sex would seem to be a merely bodily need - an urge that must be satisfied sooner or later with all the necessity of the natural laws observed by the scientist.
The question is whether the identical subject-object of history will inevitably overcome this fragmentation and also become the identical subject-object of love (assuming love combines both sex and something more mental, intellectual perhaps even spiritual). Will proletarians necessarily become better lovers? I can find nothing in "History and Class Consciousness" that implies they will.
The proletarian identity with which the new historical agents must identify utterly is a very abstract one with no connection to gender. Since the proletarian identity is the only one that matters there is plenty of scope here for excluding any more meaningful definition of the feminine and the masculine. But then the proletarian becomes indistinguishable from the Kantian. Two heroic proletarians marry to ensure that their sexual needs will not disrupt the heroic course of the proletarian revolution.
What characterises the Kantian is an instrumental approach to things that ought to be part of that organic unity that Lukacs refers to so often in the earlier sections of "History and Class Consciousness". Unfortunately a similar kind of instrumentalism seems to be implied by later sections of "History and Class Consciousness." The revolution is supposed to overcome it, but only for the proletariat considered as a whole as the proletariat ceases to be the passive object of blind market forces, industrial rationalisation and the machinations of the ruling class, becoming instead the subject of history. But since the class is everything won't individuals be treated in an instrumental way? To maintain the power of the proletariat individuals will have to make sacrifices - perhaps (heaven forbid) some individuals will have to be sacrificed. Will not the ends justify the means (especially since a defining feature of the proletariat is that they have been shorn of ideals and presumably have no commitment to the bourgeois principles that protected the rights of individuals)? Seen from the standpoint of the individual the revolution appears as the apotheosis of instrumental reason, not its overthrow.
If instrumental reason runs rampant and if gender roles pale into insignificance with the rise of a proletarian uniformity, there is little reason to think that the number of sexual Kantians will drop after the revolution.