What if I told you that microeconomic theory helps prove that dating systems where men approach women are inherently unequal? Because of an economic model called a matching market, we can algorithmically show that a heterosexual system where men approach prospective partners benefits men over women. 

In economics, a matching market is a situation where people are not simply buying and selling things. Instead, individuals are being matched with one another: workers with jobs, students with universities, kidney donors with patients. 

We can consider the simplest possible version of a binary heterosexual dating market where people are matched with romantic partners. We assume that everybody wants exactly one partner. We assume that everyone knows their preferences over the opposite sex. Man 1 has an ordered list of the women he would prefer to date; Woman 1 has an ordered list of the men she would prefer to date; and so on.

Obviously this model is an oversimplification; but using simple models allows us to examine the underlying logic of markets and systems, as well as their outcomes.

Imagine that men move first in this traditional dating system. The following steps take place:

1. Every man proposes to his most preferred partner. 
2. If a woman receives multiple proposals, she tentatively accepts the one she prefers most and rejects the others. 
3. The rejected men then propose to their next-most-preferred partner. 
4. The process continues until there are no more proposals to make.

Eventually, we arrive at what economists call a stable matching, where there is no mutually beneficial way for two people to break away from the existing arrangement. (See an animation of this process here).

Everyone lives happily ever after. Except that this stable outcome isn’t necessarily unique. There can be several different ways of matching everyone together that are all perfectly stable, and, crucially, the outcome depends on who gets to propose. If the men propose first, the result is the men-optimal stable matching: each man gets the best partner he can possibly receive in any stable matching, whereas if the women propose first, the algorithm produces the women-optimal stable matching. The men-optimal outcome is simultaneously the worst stable outcome for the women, and vice versa.

Changing nothing but which side moves first changes the entire bias of the system’s outcome. This is the result of the Gale-Shapley deferred acceptance algorithm, one of the foundational conclusions of matching theory.

For much of modern history, heterosexual dating has operated according to a remarkably similar social convention: men are expected to make the first move. The concept of men proposing to women in marriage entrenches this concept in traditional relationships.

Obviously, real dating is vastly more complicated than the economic model. People do not have perfectly ordered lists of preferred partners. Attraction is reciprocal and dynamic. People can change their minds. Sexual orientation and gender are not binary, and thankfully, most relationships are considerably more complicated than an algorithm.

The matching model isn’t a literal description of human romance, but economics gives us a particularly elegant way of understanding why it matters who makes the first move. If one side of a matching market consistently gets to propose, that side receives a structural advantage in the resulting stable matching. The proposing side gets the best stable outcome available to it; the receiving side gets the worst.

When a society tells men that they should pursue and women that they should be pursued, it isn't necessarily enforcing a harmless romantic tradition, rather it is assigning different roles in a bargaining and matching process. If that process is repeated across millions of interactions, it becomes a social institution.

The rules of a matching market can determine who benefits from the outcome, even when everyone's preferences remain the same; If we have spent generations teaching one sex to propose and the other to be pursued, perhaps we should at least ask whether dating conventions could give one gender a structural advantage before anyone has even said yes.