October 10, 2013
Douglas W. Allen, an economist at Simon Fraser University, in Vancouver, has just published a highly controversial study in the journal Review of Economics of the Household. It breaks with the conventional wisdom that there is no difference between parenting by a mother and a father and parenting by a same-sex couple.
MercatorNet interviewed Professor Allen about his findings.
MercatorNet: What has your research found about educational outcomes for children of same-sex couples versus children of opposite sex couples?
Doug Allen: There have been about 60 studies over the past 15 years or so that have asked “do child outcomes differ when the child is raised in a same-sex household." Almost all of this literature has the following characteristics: the samples are tiny and biased, the outcome measures are subjective and difficult to replicate, and the finding is always one of "no difference."
Despite the limited scientific validity of these studies, they all end with sweeping policy recommendations. It really is not a scientific literature, but rather a political literature targeted at judges, lawyers, and politicians.
Then came a paper by Michael Rosenfeld, published in Demography 2010. This paper had a large random sample and looked at normal progression though schools in the US. It was, in my opinion, the first solid piece of statistical work done on the question, and he confirmed the "no difference" finding. Later, Joe Price, Catherine Pakaluk, and myself replicated his study and found two problems.
First, he didn't find "no difference". What he found was a lot of noise, and so he was unable to statistically distinguish children in same-sex households from children in any other type of household - including ones we know are not good for children.
Second, the lack of precision in his estimates came from a decision he made to throw out children from the sample who had not lived in the same location for five years. This turned out to be heavily correlated with same-sex households. Hence, he inadvertently threw away most of the same-sex households from the sample. Without that information, he did not have the statistical power to distinguish between family types.
So, the three of us restored the sample and used the statistical technique of controlling for household stability. What we found was that children of same-sex households were about 35 percent more likely to fail a grade.
While this was going on, I was using the Canada census to look at some other questions. I noticed several things about the census that differed from the US. one. First, unlike in the US, the Canada census actually identifies same-sex couples. This solves a big measurement problem with the US census, which could include room mates, family members, and opposite sex couples as same-sex ones.
Second, the Canada census had a nice link between the children and the parents, so I was able to control for the education of the parents and their marital status. Poor performance in school is correlated with marital disruptions of parents, so this is an important control. In many ways then, the Canada census is a much better data set for addressing this question, and I decided to simply redo the Rosenfeld study using this data. (The census does not record progress through school, so I examined high school graduation rates instead).
So, what did I find? First, I simply looked at how any child in a gay or lesbian home did compared to children from married, cohabiting, and single parent homes. Most of the discussion in the paper compares children in same-sex homes to those in opposite sex married homes, but a reader can do all of the comparisons by looking at the tables.
I found that on average, children in same-sex homes were about 65 percent as likely to graduate from high school, compared to similar children in married opposite sex homes. That finding seems very similar to the one we found in the US regarding normal progress. Next, I wondered if the gender composition mattered at all, so I separated out the boys and girls. I was very surprised by the results.
On the boy side, I just found a lot of noise. Some boys do well in same-sex households; some do quite poorly. I cannot statistically determine the effect.
Just looking at the point estimates, boys in lesbian homes are about 76 percent as likely to graduate, in gay homes they are about 60 percent more likely to graduate. But neither of these are statistically significant, meaning they cannot be distinguished from zero.
Girls are another story. First, the estimates are very precise. Second, they are low. A girl in a gay household is only 15 percent as likely to graduate, in a lesbian household about 45 percent as likely. The result found by lumping all of the children together is being driven by this girl effect. This result is very robust, I tried many specifications, sample restrictions, and estimation techniques, but it always remained.
So, my paper no only rejects the "no difference" consensus, it points to a finding -- that if upheld by other studies -- seems incredibly important.
It's particularly hard on girls, isn't it? Why is that?
Allen: It is important to point out that I make no theoretical claims in the paper. I'm simply pointing out an empirical finding that is based on a high quality large random sample, and which is inconsistent with almost everything that has come before.
Having said that, as an economist, I would make the following speculation: specialization. It makes sense to me that fathers and mothers are not perfect substitutes. Indeed, mothers may provide some parenting services that a father cannot provide, and fathers may provide parenting services that mothers cannot. These services may be necessary for girls but not necessary for boys.
For example, I've been told by medical people that when a biological father is present in the home, daughters begin menstruation at an older age. Later menstruation is likely correlated with delayed sexual activity, etc., and this may lead to a better likelihood of high school completion.
It seems to me there could be dozens of channels this could work. As a father of two girls and one boy, I've often had discussions with other parents noting that with boys you just have to keep them fed and away from explosives, but with girls rearing is a little more complicated. That's a poor attempt at humour, but the bottom line is this is an interesting question that deserves to be looked at.
One explanation of poor school performance in general is that children of same-sex couples may be discriminated against at school. This seems less likely given the different finding between boys or girls. Or at least one would have to come up with a different more complicated story of discrimination.
This turns the conventional wisdom on its head, doesn't it? Most people think that there is no difference. Was there anything wrong with the quality of previous research?
Allen: I think I've answered this above. I should point out one other thing, however. I've read just about every paper on this subject that has been published since 1995. Although many of them claim to find "no difference", they often do find something. Again, the finding is coming from a biased small sample, but differences are found. For example, children growing up in same-sex homes are more likely to experiment with alternative sexual lifestyles, etc.
I should also point out that not all studies are created equal. For example, an Australian sociologist named Sotirios Sarantakos has done considerable work in the 1990s that (though not random) uses large longitudinal studies of objective, verifiable, and hard measures of performance. He finds many differences with children in same-sex households in terms of mathematics, language and other school performance measures. Interestingly, his work is never referenced in most literature surveys. Again, this points to the political nature of this literature.
Your conclusions are based on Canadian census data. Why is that better than US data?
Allen: I've mentioned this above, but let me give more detail. The US census does not identify same-sex cohabiting or married couples. So how did Rosenfeld and others find them? They looked at a series of questions: for example, what is your sex, are you married, what is the sex of your spouse? If someone answered male / yes / male, then this would be considered a gay couple.
The problem with this is that it can lead to a number of measurement issues. Suppose I'm a married man, bunking with another man in a work camp (this may seem far fetched, but it is a real example). When I answer the survey I say I'm male, I'm married, and I'm currently living with a male. I may get counted as a same-sex couple even though I'm not. This can happen with same-sex family members who live together, room mates, and others.
There is also the problem of random mistakes. No one fills out a form perfectly, and sometimes the wrong box is ticked off. Because there are so many heterosexuals compared to gays and lesbians, it only takes a small fraction of seniors to tick off the wrong sex box and it can swamp the same-sex sample. The Canada census avoids these problems. It not only identifies same-sex couples, but they must be in a cohabiting or marriage relationship.
Canada has also had legal same-sex marriage before the census was taken. Many have argued that Canada is more open and accepting of same-sex marriage. As a result, the reporting bias is likely lower in Canada than in the US.
Finally, as mentioned above, I was able to control for the marital history of the parents. This also turns out to be statistically important, and in the paper I show what happens when this is not controlled for. Children in same-sex households are much more likely to come from a previous heterosexual marriage than from adoption or other means. Divorce, however, reduces the likelihood of graduation. If you don't control for this effect, children of same-sex households look like they do even worse at graduation. So this is an important variable to consider.
Does your study prove conclusively that there is no difference? What questions does it raise?
Allen: Assuming there are no mistakes in the study, it rejects the claim that there is "no difference." I personally think that in social science we should never place too much weight on a given study. It is important that we look at evidence from different countries, etc. I would say this study builds on a few others that are questioning the long held consensus. An examination of the literature shows that the consensus is built on only a series of preliminary work. Now that people have started looking at this more seriously, we're finding no evidence for that conclusion.
In such a contentious field, will your study make an impact upon the public debate?
Allen: I don't know, but I suspect it will have little impact. The debate seems to have shifted from the statistical lab to the bumper sticker. The concept of "marriage equality" and the alignment of same-sex marriage rights with the civil rights movement seems so powerful that I doubt one little study will matter much.
If there is merit to the study, and if there really is a difference that matters, I think it is much more likely that 20 years from now we'll be asking "how did we get here and how can we clean up the mess" -- in much the way we now wonder how we ended up in a world where so many children are raised by single parents.
Sociologist Mark Regnerus published a paper which came to a similar conclusion last year and was all but crucified by his colleagues and activists. Do you expect a similar reaction?
Allen: Prior to the publication of his paper I was unaware of Professor Regnerus' existence. Because I was working in this area I saw what immediately happened. I was struck by the hypocrisy of those who attacked him.
Here was someone who had looked at the literature and decided to do something better. There were tiny samples, so he went and found a large sample. There was nothing but bias and snowballing (the procedure of asking friends to join a study), so he did a random procedure. There was way too much soft-balling of questions, so he asked a series of quantifiable ones. He was trying to improve the work, and that is commendable.
Was his study perfect? No, but a study never is. His great error, of course, was that he found the wrong answer. Those who came later and complained about the things he did should have been equally outraged by what had come before. Had Regnerus found otherwise, they would have lauded his work as path-breaking.
I rather suspect this will not happen to me for a number of reasons. First, after the Demography comment came out last year, my university received several letters (sent to the president, various other administrators, and many of my colleagues) demanding that I be fired. These were the same tactics that were used against Professor Regnerus.
Fortunately for me, I'm well known and respected at my institution and we have a strong sense of academic freedom. Indeed, Simon Fraser University has recently been ranked as one of the safest universities to express ideas that may be politically incorrect.
Second, my study only looks at one margin of child performance: high school graduation. Professor Regnerus looked at many and in many ways he found more problems than I found.
Third, my sample is a 20 percent sample of the Canada census. No one can claim I have a small biased sample or that the agency in charge of collecting it is not trustworthy. Fourth, Professor Regnerus was first, and I think being first is much more likely to come under fire. Fifth, the US Supreme Court has already made a decision on Prop 8 and DOMA, so much of the incentive to attack has passed.
Having said that, I have come under some attack, and I would like to relay one incident that has happened.
Last week I received an email from David Badash, the editor of The New Civil Rights Movement, a prominent gay rights website. In it he said he'd heard about the study, wasn't happy about it, but wanted to talk to me before he wrote about it. I emailed back, sent him a copy, and invited him to ask me any questions about the work.
On Monday, when I arrived at work, there were a number of colourful emails waiting for me, calling me all kinds of four-letter words. I soon realized that these were coming from people who had read Mr Badash's blog page.
So I went to have a look myself. What I found was a mixture of personal attacks, misunderstandings and misrepresentations of my work, and a general meanspiritedness. Just the opposite of what I've always believed a public discussion should be.
So, maybe I'm naive, maybe the attacks will come. I hope not. Anyone who wants to read my work is welcome, and I'm willing to have a reasonable discussion about it with anyone.
Douglas W. Allen is the Burnaby Mountain Professor of economics at Simon Fraser University in Burnaby, British Columbia, where he earned his undergraduate degree. He has a PhD in economics from the University of Washington, and is the author of four books and numerous articles.