Why do people criticise the 'one-penis policy' for bisexual women?
A one-penis policy lets a woman date other women but not other men. Critics argue it treats relationships between women as not 'real' or threatening, manages a man's insecurity by restricting his partner rather than doing his own work, and erases a bisexual woman's genuine attraction to men. It's widely seen as biphobic.
A one-penis policy (OPP) is a rule, almost always set by a man, that his woman partner may have other women partners but no other men. On its surface it can look like openness, but the critique is pointed: it implicitly treats relationships between women as not real competition — not 'real' relationships at all — while reserving genuine threat status for other men. That's a diminishment of queer women's relationships dressed up as a permission.
For a bisexual woman specifically, the OPP erases half of her orientation. It treats her attraction to women as acceptable precisely because it's not taken seriously, and her attraction to men as the dangerous part to be controlled. Many bisexual women experience it as being told that the queer part of them is fine only because it doesn't count.
The deeper objection is structural: an OPP manages a man's insecurity by constraining everyone else's behaviour rather than by his doing the internal work. Even writers sympathetic to transitional safety rails argue that if such a rule appears at all, it should be named honestly as one person's insecurity-management, be explicitly temporary, and be retired as the relationship matures — not presented as a principled ethic.