Will Men Take The Pill? Research & Game Theory Say Yes

Aaron Hamlin
6 min readDec 31, 2015


The Sirens of the Internet

When you write articles, one piece of advice people give you is to not read the comments. It’s the internet. The internet is crazy. But like a Siren that pulls us in, we can’t help ourselves.

We hear about how Vasalgel is going to be injected into the testicles (that’s not how it works), and we hear about how each gender is somehow conspiring against the other to keep male birth control from happening.

Another issue we hear a lot is that men simply aren’t going to take a pill, and that it’s not logical for women to think that a guy will take the pill. But that’s wrong. We know it’s wrong because of empirical survey data, and we know it’s wrong because of basic game theory.

Let’s Be Clear: Men Want Better Options

Survey data published in the journal Human Reproduction indicates that at least half of US men would take a new male contraceptive, with a pill form having 70% acceptability among those interested. Plus, this study talked about a hormonal approach. All the male contraceptives that we talk about are nonhormonal (for example: Gendarussa and anti-Eppin). So we’d expect nonhormonal acceptability to be even higher.

We know guys are interested. And they should be. The stakes are high. Besides the general desire to control whether we cause another child to be crawling around, accidental fatherhood is expensive. Expensive as in $100K over 18 years child support expensive. Whether you’re in a good relationship or not, having a kid costs a lot of money, which is why we don’t want to have one every time we have sex.

An Introduction to Game Theory

It turns out that the incentive is very high for a guy to take a pill, even if he doesn’t know for sure what his partner is going to do. And we can analyze that using game theory. Game theory is when you have multiple people trying to logically optimize their personal outcome through strategy while simultaneously considering others’ decisions.

In game theory terms, a man’s best strategy is going to be to take the pill. Let’s take a look at the different scenarios.

Scenario 1: Man Doesn’t Take Pill & Woman Takes Pill

Here, the guy get’s the luxury of not having to take anything, and his partner gets the joys of hormonal contraception. Initially, it may sound like this is a great situation for the guy — all the benefits but none of the responsibilities. But a closer look says otherwise.

Oral contraceptives for women are highly effective. We’re talking three pregnancies out of a thousand users for the first year of use. That’s pretty awesome. That is, it’s awesome until you see that’s only for perfect users. That means remembering to take it every day and at the same time. Unfortunately, this isn’t the real world for most women.

In the real world, half of women report missing at least one pill during their last cycle. This is why the real-world pregnancy rate for Pill users is almost one out of ten for the first year of use. I’ll point out the obvious here and remind you that you reroll that risk die every subsequent year you want to avoid a pregnancy while also having sex. Tac on multiple years and you can see your overall pregnancy risk jump substantially.

That risk is enough to make anyone nervous. This is also why women might consider more effective methods such as intrauterine contraceptives or implant devices. We’ll just focus on the Pill with our model, however.

Scenario 2: Man Doesn’t Take Pill & Woman Doesn’t Take Pill

This is really bad for the guy and the woman. Unless there are fertility issues, there is a very high risk of pregnancy if neither person is using birth control. This is not what you want as a guy.

It’s starting to become clear why it’s such a good idea for the man to take a pill if it’s an option. You can see in the bottom righthand corner by the zero values that this is the worst outcome for the man and woman. (The man’s value is the first number.)

Let’s look at the worst case scenario if a guy takes the Pill.

Scenario 3: Man Takes Pill & Woman Doesn’t Take Pill

It’s tough to know how effective a male pill would be, so we’re using the female Pill as a proxy. We’ll assume that forgetting to take pills is just a human thing and men will be no better than women in practice.

Here, the guy has the burden of taking the Pill, though there is a silver lining. As the pill taker, the guy gets the ability to be a good pill taker. He has the advantage of control over his own fertility.

So the pregnancy risk here looks the same as if the woman were taking the Pill. Still, there’s better.

Scenario 4: Man Takes Pill & Woman Takes Pill

Both the man and the woman could be taking a Pill. On the downside, both partners have to put up with taking something. On the upside, the risk of an unwanted pregnancy would be very low. Low enough not to get super nervous. And that’s probably worth putting up with taking the Pill. Take a close look at the square where neither person takes a pill and you’ll see why being risk averse is such a good idea.

John Nash Would Agree

Dr. John Nash

What’s interesting here is that there’s always incentive for each person to take the Pill. If neither are taking the pill, there’s a better outcome if either starts taking it. If the guy is taking the pill, he’s motivated to keep taking it. If the woman is taking the pill, she’s motivated to keep taking it.

This also makes both partners taking the pill the sweet spot where neither would want to unilaterally change their behavior. For you Beautiful Mind fans, this is called the Nash Equilibrium.

The downfall here is that this model assumes both individuals understand their pregnancy risk. Game theory models — like any model — involve assumptions. And contraceptive pregnancy rates are not always understood by the general population.

The Best Worst-Case Scenario

For a guy deciding to take the Pill, his worst case scenario is that he gets some protection against pregnancy. For a guy deciding not to take a Pill, his worst case scenario is a very high risk for an unwanted pregnancy. This means that for a guy who wants to minimize his risk, his best option is to take the Pill.

Answering the Sirens

This analysis means that both empirical survey data and game theory say that men would take a Pill if it were available. That’s promising because better male birth control has the potential to do a lot of good. But does that mean we can expect more reasonable comments on male birth control articles? Probably not.

Originally published at www.malecontraceptive.org on December 31, 2015.