The Science on Same-Sex Marriage

A round up of studies on same-sex marriage, divorce, children, and monogamy.

Last week, the U.S. Supreme Court heard oral arguments in two cases challenging legal restrictions on same-sex marriage. Proponents and opponents sought to cudgel one another with sociological and psychological studies aiming to prove that science is on their side. Well, what does the science say?

Impact on Traditional Marriage

Some opponents told the court that same-sex marriage will undermine conventional marriage among heterosexuals. So what do the data say about how legalizing gay marriages affects conventional marriages?

A 2009 study by University of Sherbrooke economist Mircea Trandafir investigated the effect of the legalization of same-sex marriage in the Netherlands, the first country to recognize same-sex marriage. In 1998, the Dutch created registered partnerships, which are open to all couples, and in 2001 a law allowing full same-sex marriages. His analysis found that same-sex marriage leads to a decline in the different-sex marriage rate, but not in the different-sex union (marriage plus registered partnership) rate. In other words, Dutch heterosexual couples are taking advantage of the “marriage lite” registered partnership alternative.

At the time of Prof. Trandafir’s study, the chief difference between registered partnerships and marriage was that the former could be dissolved at the civil registry by mutual agreement. In a 2012 West Virginia Law Review article, Mercer School of Law professor Scott Titshaw shows that the political compromises provoked by the initial refusals to extend full marriage rights to same-sex couples result in a proliferation of civil union alternatives. Prof. Titshaw agrees with Prof. Trandafir that different-sex couples increasingly find the new marriage alternatives attractive; in effect, refusing to give full legal recognition to same-sex couples ends up diminishing the status and benefits associated with conventional marriage for everyone. Ironically, conservatives by opposing the extension of full marriage rights to gay people have ended up weakening the institution they sought to protect.

The Divorce Rate

Sweden legalized same-sex civil unions in 1995 and gay marriage in 2009. A 2011 demographic study from researchers at the University of Stockholm reports that since 1999, after decades of falling, both the marriage rate and the fertility rate have trended upward and the divorce rate is down.

Massachusetts was the first state to legalize same-sex marriage in 2004. In 2003, the divorce rate in Massachusetts was 2.5 per 1,000 residents, and it fell to 1.9 by 2009. The Massachusetts marriage rate jumped 15 percent in 2004, as many same-sex couples chose to get married, but since has remained stable. Interestingly, the states that permit same-sex marriage tend to have lower divorce rates than those that ban same-sex marriage.

A 2004 study of registered partnerships in Sweden reported that gay male couples were 50 percent more likely to divorce than were heterosexual couples. Lesbian couples were nearly three times more likely to divorce than were heterosexual couples.

 But how salient are higher divorce rates among gays and lesbians for making public policy? Consider that a 2008 study in the journal Family Relations by Rice University sociologist Jenifer Bratter found that in the U.S. black-husband/white-wife marriages were twice as likely to end in divorce as white/white couples, and Asian-husband/white-wife couples were 59percent more likely. Yet few would argue that interracial marriages should be prohibited because their children are at substantially greater risk of experiencing the social, psychological, and economic disadvantages stemming from a higher interracial divorce rate.

Having Kids

Nearly 20 percent of same-sex households—i.e., 115,000—reported having children, and 84 percent contained children biologically related to one of the householders. In comparison, 94 percent of different-sex married couple households with children reported living with their own children. A study issued in February by the Williams Institute, a gay public-policy think tank at the law school of the University of California, Los Angeles, reports that 37 percent of “lesbian, gay, bisexual and transgender” (LGBT) adults have had a child at some time in their lives. In addition, the report notes that as many as six million American children and adults have an LGBT parent.

 Opponents and proponents of same-sex marriage spar fiercely over the data about how children fare in same-sex households. On March 21, when the American Academy of Pediatricians issued a statement in favor of same-sex civil marriage, the group also published a technical report that comprehensively looked at the available research on the well-being of children living in same-sex households. The report noted that a big problem with current research is the small sample sizes of many of the studies. An additional problem is that most of the children in these studies have been through divorce before living in a same-sex household. Divorce is well known to have deleterious effects on the well-being of children.

However, data are reassuring from the National Longitudinal Lesbian Family Study, which includes 78 lesbian families who used donor sperm to have children and have been followed since the 1980s. A 2012 study compared quality-of-life measurements of adolescents from lesbian families with those from a matched set of adolescents raised in different-sex homes. The researchers reported that “adolescents reared by lesbian mothers from birth do not manifest more adjustment difficulties (e.g., depression, anxiety, and disruptive behaviors) than those reared by heterosexual parents.”

 By the time that their children were age 17, some 55 percent of the lesbian couples had separated compared to 36 percent of heterosexual couples in the National Survey of Family Growth. However, children from separated lesbian couples don’t appear to manifest the social and psychological problems often found among children whose heterosexual parents are divorced. The better scores achieved by the children of lesbians, the researchers point out might result from the fact that 75 percent of the separated lesbian couples shared custody, whereas 65 percent of divorced heterosexual mothers had sole custody of their children.

Editor's Note: We invite comments and request that they be civil and on-topic. We do not moderate or assume any responsibility for comments, which are owned by the readers who post them. Comments do not represent the views of or Reason Foundation. We reserve the right to delete any comment for any reason at any time. Report abuses.

  • Fist of Etiquette||

    Way to take all the romance out of marriage, Bailey.

  • Adam.||

    From my perspective I am intellectually interested in the effects of same sex parents on children, I could imagine there might be some measurable differences but I can also imagine that for foster children any caring parents would be better than being a ward of the state. From the monogamy\divorce perspective, I really don't see it as any of the public's business. But then again that's why I frequent this site.

  • alice846||

    If you think Christopher`s story is astonishing, Earn 10 to 50$/hr working from home with Google! I work two shifts 2 hours in the day and 2 in the evening. And whats awesome is Im working from home so I get more time with my kids I follow this great link Read More

  • Tony||

    I can barely stand to be in the same room as a significantly less intelligent adult, let alone a child. Of course I was against cats until my boyfriend brought one home. Do children scratch furniture? I didn't have to train my cats to use their litter boxes, will I have to train a child to use his?

  • ZackTheHypochondriac||

    what made you change your mind on the cat?

  • Tony||

    She was so bitchy and diva-esque you couldn't help but love her.

  • ||

    I didn't have to train my cats to use their litter boxes, will I have to train a child to use his?

    You don't have to...but I think wearing a diaper their entire life will outlast any "problems" from having gay parents.

  • ||


    I can barely stand to be in the same room as a significantly less intelligent adult, let alone a child...I didn't have to train my cats to use their litter boxes, will I have to train a child to use his?

    I assume, then, that if you met yourself as a child, you wouldn't be able to stand yourself. And, yes, you don't remember, but you pooped and wet yourself constantly.

  • ||

    I can barely stand to be in the same room as a significantly less intelligent adult

    That must severely limit your social life.

  • ZackTheHypochondriac||

    PM| 4.6.13 @ 4:48AM |#

    I can barely stand to be in the same room as a significantly less intelligent adult

    That must severely limit your social life.

    are you saying he's really smart?

  • SumpTump||

    I like the direction that is going ion. WOw.

  • ZackTheHypochondriac||

    R. Bailey, just out of curiosity have you heard of David Pearce? What do you think of him and/or the use of genetic engineering and biotechnology to end all suffering?

  • cavalier973||

    *A 2004 study of registered partnerships in Sweden reported that gay male couples were 50 percent more likely to divorce than were heterosexual couples. Lesbian couples were nearly three times more likely to divorce than were heterosexual couples.*

    This is very interesting. My inferences concerning the same-sex lifestyle is that the lesbians tend to be more relationship-oriented, while the homosexuals tend to be more focused on sexual intercourse. Hence, I would have thought male couples would be more likely to split up than female couples.

  • ||

    Gross generalization, but watching my hetero friends' relationships, women were the ones pushing to take the relationshis "to the next level" so on aggregate perhaps lesbian relationships ratchet up to marriage more quickly and with less of a trial period.

    Again, that's totally conjecture, and I have have straight friends who got married obscenely quickly, gay friends who are serial monogamists (monogandrists?) and lesbian friends who are absolute players, but with large enough numbers, those small tendencies might quickly add up.

  • Warren Norred||

    It seems to me that the practice of comparing all LGBT married people to all hetero people is flawed, IF the goal is to determine the impact of "LGBTness" to marriage. It seems that practicing homosexuals tend to be more sophisticated and far more educated than the norm.

    To elaborate, I'd assert that homosexuality is a "first-world problem", so to speak, as it doesn't show up much in lands where people are less comfortable and a strong safety net for old people has eroded the connection between generations.

    So if we are going to try to compare stats on marriage for heteros v. all non-heteros, it seems that we'd want to start to control for the other demographic factors that have a significant impact. The probable easy place to start is to filter for college degrees. One could even just start by filtering for graduate degrees, and get a very tight control group fairly easily.

  • triclops||

    Since we know being poor and dark lead to poorer outcomes for the kids,and have poorer marriage outcomes, shouldn't we disallow them from getting married too?

  • susandaved||

    until I looked at the paycheck ov $6863, I did not believe brother truly making money in their spare time from there pretty old laptop.. there best friend has done this for only eleven months and by now paid the loans on their mini mansion and bought themselves a Lotus Carlton. this is where I went and go to home tab for more detail ..

  • SIV||

    National Longitudinal Lesbian Family Study

    Turkey basters are better role models than men.

  • ||

    While this can be debated from a multitude of angles, I choose to look at it from a separation of church and state angle: IF marriage is is God's realm, why is the church groveling before Caesar to define marriage? Why not instead get Caesar out of it and have everyone form corporations. Incorporate for Caesar and Marry for God. Yeah places like VA will have to wake up to the fact that SCOTUS shot down anti-sodomy laws in 2003 under Lawrence v. Texas, but separating the 2 ensures that Caesar can't tell the church who can marry and the church can't tell Caesar who can join/have sex/mate/?. Well, unless you are trying to control people and restrict freedoms.

    Unfortunately, the next argument will be that we are destroying traditional marriage in favor of getting tax write-offs on the family vehicle.

  • DarrenM||

    Marriage is not "God's realm". This is the mistake (possibly willful) that many appear to make. In general, marriage has existed in every location and culture regardless of local beliefs because the fundamental relationship between man and woman are pretty much the same all over.

  • DarrenM||

    In fact, nearly half of male same-sex spouses (47 percent) had an explicit agreement that allowed for non-monogamy. In comparison, the General Social Survey reported in 2010 that 19 percent of men and 14 percent of women they had been unfaithful at some point during their marriages.

    What does one have to do with the other? In the first case, the parties were perfectly happy with the partner having extra-relationship affairs with no indication of actually how often this occurred. And this was only with "explicit agreement". How many had no need of an "explicit" agreement? In the second case, it's just the opposite. There is no indication men or women were accepting of the affairs or not, only that they had them, which is nothing new.

  • mayajan67||

    uptil I saw the draft ov $7576, I have faith brother woz like really making money part-time on their apple laptop.. there great aunt haz done this 4 only eleven months and by now cleard the dept on their cottage and bourt a gorgeous BMW. we looked here,


Get Reason's print or digital edition before it’s posted online

  • Video Game Nation: How gaming is making America freer – and more fun.
  • Matt Welch: How the left turned against free speech.
  • Nothing Left to Cut? Congress can’t live within their means.
  • And much more.