There’s a lot to love about the Internet.

When I met my husband, I asked him for his number, but never called. Frustrated, he Googled me and found a directory in which my email address was listed. In a message, he asked me for my number, and the rest, as they say, is history.

That was over a decade ago; the only thing my husband could find about me on the Internet back then was that address. Today, the amount of information available to a potential couple before their first date is vast, and it is information that used to be inaccessible until you got to know someone, sometimes quite well. My husband and I had to sort out what we had in common and what we didn’t the old-fashioned way, by going out to dinner where we learned that even when we didn’t agree we still enjoyed the conversation. Had we been able to choose our mates based on predefined criteria, we probably would have never gone on that first date. And the thing is, the increased ability to sort out potential mates according to predefined preferences may also be making the United States more politically polarized.

The demographic makeup of the people who are most likely to meet their spouses online is the same as the people most likely to vote, contact their congressmen, and be members of the interest groups that influence Washington lawmaking.

In 1999, only two percent of American singles had used an online dating service in their search for a partner, but that number has grown exponentially in the years since. According to a recent study published, one third of all marriages now begin online. Of those, 45 percent met through an online dating service and another 20 percent met through a social networking website. As the authors note, “Traditionally, people met their spouse in off-line settings: work, school, social gatherings, and so forth.” This is still true. According to the study, among couples who first met in person, a majority did so either at work, school, or through a friend. Approximately another 20 percent met at a bar or club or at some other social gathering.

People who use Internet dating sites are choosing who to date based on criteria that are highly correlated with political preferences, according to a study published in the most recent edition of the academic journal Political Behavior. As a result, the study suggests, there may be long-term consequences for political polarization: not only are such couples more likely to move to the ideological extremes because they lack access to contradictory opinions, they also are likely to produce children who hold ideologically extreme positions. The end result is a more polarized America where more and more people cannot understand how others could possibly think differently from themselves.

The ability to filter relationships based on factors that correlate highly with political preferences is possible only due to the advent of personal webpages, social media, and dating websites. Such mechanisms enable individuals to find potential mates far outside their immediate social circles and learn far more about their preferences and attitudes than is possible when people meet through face-to-face social interaction. The Internet also allows people to be pickier about who qualifies as “acceptable” before they ever have the chance to meet. As a result, we now can limit our exposure to contradictory political information in advance—information that political scientists have determined to be critical in making us tolerant citizens.

For decades, political scientists have studied how people become Democrats and Republicans. We’ve learned that there is a strong transfer from parents to children. In other words, you are more likely to be a Republican if both of your parents are. But the transmission of party identification from parent to child is less than perfect, and one reason is that, historically, lots of people had parents who didn’t identify with the same party. Mom might be a Democrat while dad is a Republican. In such situations, the child is far more malleable in his or her partisan choice. Another reason is that it is the young adult years when people are exposed to new information that challenges what they learned from their parents and which helps them to develop stable partisan identities. And one of the greatest ways in which they get to know contradictory ideas is from people they have intimate conversations with, like the people they date.

The effect of mixed politics partnering is important: When in a relationship where two people do not identify with the same party, individuals tend to be moderated by their partner and less stalwart in their ideas. Sometimes, one of them might even change their party identification to match the other’s preferences. According to Professors Laura Stoker and M. Kent Jennings, the “gender gap”—the term used to describe the fact that women are far more likely to vote for a Democratic candidate and to identify as liberals than men are—is drastically smaller for people in long-term relationships where the partners shared different partisan and ideological positions when they met than among non-married individuals. And even if they don’t change their positions, when people are exposed to divergent political viewpoints from people they spend time with, they tend to be far more tolerant of opposing views.

Unfortunately, this has some serious consequences for democracy. When people do not understand the rationale behind contradictory beliefs—something we learn from talking with friends and loved ones who hold opposing views—we tend to be less tolerant toward the opposition. Some research even suggests that when we lack this information, we are more likely to think the government is illegitimate when we are on the losing side of an election. The next time you see a bumper sticker that says, “He’s not my President,” you may want to ask the person if they met their spouse online.

Importantly, the demographic makeup of the people who are most likely to meet their spouses online is the same as the people most likely to vote, contact their congressmen, and be members of the interest groups that influence Washington lawmaking (upper income college graduates).

There is an old adage that says “opposites attract.” But in the era of the Internet, they may never get the chance to. As a result, recent research suggests, our political process may become more combative and even more gridlocked than it is now.