There's an interesting evolutionary benefit for some women if the consequences of casual sex are high. Albin Lohr-Jones/Pacific Press/LightRocket via Getty Images

In the wake of the U.S. Supreme Court's decision to overturn abortion rights, many people have strong opinions.

What drives people to get abortions?

It is common to hear explanations about the sanctity of life. If such beliefs were driving anti- abortion attitudes, then people who oppose abortion might not support the death penalty, and they would support social safety net measures that could save newborns' lives.

The field of evolutionary social science suggests a different explanation for anti- abortion attitudes.

Why do people care what strangers do?

Getting more copies of your genes into the next generation is the coin of the realm. What strangers do has little effect on your fitness. It's a mystery why people in Pensacola care so much about what happens in the bedrooms of Philadelphia and Los Angeles.

A conflict of sexual strategies is the solution to this puzzle and one answer to what is driving anti- abortion attitudes. People who are sexually restricted tend to shun casual sex in favor of long-term relationships and children. People who are sexually unrestricted are more likely to pursue a series of different sexual partners.

Evolutionary fitness is affected by sexual strategies.

The crux of the argument is that other people's sexual freedom is a threat. Sexually restricted women are more likely to have children early in life. These choices are just as valid as a decision to wait, but they can be detrimental to women and leave women more economically dependent on husbands.

Women who are open about their sexuality can destroy their lives and livelihoods. Women who are sexually restricted benefit from other people not being able to have sex. Men who are sexually restricted tend to invest a lot in their children so they benefit from prohibiting people from having sex.

Benefiting from making sex more costly

Evolutionary social science states that restricted sexual strategists benefit by imposing their preferences on society.

How can they achieve this? Making casual sex more expensive is what happened.

Women are forced to endure the costs of having a child because of the ban on abortion. The price of casual sex can go up if there is a hike.

A justice who opposed abortion when it came before Mexico's Supreme Court in 2008 said that a woman in some way has to live with the phenomenon of becoming pregnant. She has to deal with the effects of the whole period when she doesn't want to keep the product.

If people are forced to suffer the effects of casual sex, less people will engage in it.

There is no correlation between abortion restrictions and the cost of sex. The life threatening dangers of childbirth and the disproportionately high costs of pregnant women make them responsible for child care. Women who are denied an abortion are more likely to end up in poverty.

This is not a conscious phenomenon. Political science and evolutionary social science agree that people's strategic interests shape their attitudes in ways that are self- benefiting.

Resolving awkward contradictions in attitudes

Common explanations aren't the real drivers of people's attitudes on either side of the abortion debate

People's stated religious, political and ideological explanations are often rife with strange contradictions. Many people who oppose abortion also oppose contraceptive use.

The contradictions are easy to resolve from an evolutionary point of view. People who are sexually restricted are able to increase the cost of sex. It costs more when people can't get legal abortions or prevent pregnancies.

Predicting which attitudes travel together can be difficult. If sexually restricted people associate something with sexual freedom, they should oppose it.

Researchers have found that people who are sexually restricted oppose abortion and birth control because they think homosexuality is associated with sexual promiscuity and recreational drugs. Some of the concerns that have yet to be tested include trans rights, premarital sex, what books children read, and equal pay for women.

We don't know any other theories that predict these bedfellows.

Behind the link to religion and conservatism

Religion and social conservatism are associated with anti- abortion attitudes.

This perspective suggests that a restricted sexual strategy can encourage people to become religious. What's the reason? Some scholars suggest that people adhere to religion because of its teachings. Participants in a study reported being more religious after being shown photos of attractive people of their own sex.

Sexually restricted people tend to invest a lot in parenting, so they stand to benefit when other people follow certain rules. Social conservatism is similar to religion in that it promotes parent benefits and promotes family stability. Some research shows that people don't just become more conservative with age. People become more conservative as a result of having children.

Restricting everyone to benefit yourself

There are many different answers to the question of why. Some factors play a role in people's abortion attitudes.

People's sexual strategies also do.

The research suggests that restricted sexual strategists make everyone else play by their rules. This group may be taking aim at birth control and marriage equality in the future.

The Conversation is a news site that shares ideas from academic experts. You can subscribe to our weekly newsletter if you like it.

It was written by Jaimie Arona Krems, Oklahoma State University.

You can read more.