Wright, Elizabeth. Lacan and Postfeminism. Cambridge: Totem Books, 2000.
The logic of the sexualtion formulae produces two sets of speaking beings not in a complementary relation to each other. Crucially, the formulae do not plot which sexual position a subject may take up — they are not hetero-sexuation formulae.
What they reveal are the historical limits of the possibility of change. They are nothing to do with a particular subject’s object-choice, which can go across biology. But however variable object-choice may be, society will still demand a binary of some kind, whatever the biology of human beings might become in the far-flung future. There will still have to be the equivalent of a ‘castration’, without which the entry into language would be foreclosed.
For Lacan, these formulae are concerned with how a speaking being experiences sexuality on the level of the psyche. They have nothing to do with biological sex, neither with the love of a man for a woman, nor that of a man for a man, nor that of a woman for a woman. This implies that a biological male can inscribe himself on the female side and biological female on the male side. Each speaking being can choose to inscribe itself on either side, although this will be a ‘forced’ choice, imposed by the parameters of the history of the subject’s unconscious (31-32).