The legalization of same-sex marriage has been making headlines in America, but one topic that doesn't get as much attention is that of same-sex couples adopting children. What makes the issue of adoption intriguing is that you're not simply talking about a union between two consenting adults of the same sex. You are now throwing in another party, i.e., a child [or children]. As the thought-terminating cliché goes, "Think of the children!" Children are particularly interesting from a libertarian philosophy (see here, here, and here) because they aren't fully autonomous individuals with mens rea, but still deserve respect and consideration because they are human beings. As such, let's go with the assumption that the welfare of the child matters in this discussion.
Some will argue that it's because the optimal family arrangement is one's biological mother and father, and others will argue that having the biological differentiation of one mother and one father is best for the child as the basis for their claim. They argue that as such, same-sex parenting is not only not ideal, but can actually harm the child. I'll get into the probability of that being the case momentarily, but let's ask another question: what if they're wrong? What if by not allowing same-sex households to adopt, you keep the child in a considerably worse situation? If the anti-gay side is wrong in their claim, then they have actually caused damage of many children. There are many children who are in the foster care system. Although foster parents should be lauded for taking in these children, it's hardly a stable or emotionally healthy for the child. As Ezra Klein astutely points out, "The idea that there is something so wrong with same-sex households that it would be preferable for these children to go two or four or six years without parents--an idea, again, that has little to no evidence behind it, and that is in fact contradicted by most of the evidence--bespeaks a homophobia so deep that it is hard for me to believe it could persist long among people who actually know any children in the foster system, and who actually know many gay couples."
Whether we're talking about the social costs of carbon, whether guns kill people, or any other policy, we have to ask about burden of proof when someone is making a claim. In this instance, the anti-gay argument is that same-sex households are suboptimal. The burden of proof goes to whoever is making the claim of the existence of something, not the one being skeptical of the claim. If the burden of proof went to the skeptic, then we would have to accept the existence of flying unicorns and the Flying Spaghetti Monster. To avoid giving credence to unsubstantiated claims, we ask that people provide some sort of credible substantiation to support a claim. This is especially true when discussing public policy and peoples' lives are affected. One of the premises behind public policy is about being able to assess the risk of a "clear and present danger." Risk assessment, or more specifically, cost-benefit analysis, is vital to determining public policy, and if you're going to be spending taxpayer dollars or using the government to ban something, you better be able to come up with something other than your perception of what a family should like as a basis for policy, or G-d forbid, anti-gay biases. Otherwise, you'd open the floodgates of ridiculousness in the world of public policy, and we'd have to call on the government to prepare for a number of unsubstantiated threats, including an alien invasion, an infestation of leprechauns, the coming of the Rapture, or the invasion of Mozambique because you're under the misimpression that they are an actual national security threat.
If we're going to make a policy decision based on the claim that same-sex households are suboptimal, it better be backed up with evidence adequately describing the benefits and harms, or opponents should simply back off because they don't have a leg to stand on, which is also how I feel about those who say genetically modified food is bad for you. Asking for evidence to support a claim isn't to much to ask for, is it? I think not, but good politics has a propensity to get in the way of good public policy. With that out the way, let's take a look at that evidence, shall we?
For those whose raison d'être it is to undermine families with same-sex parents simply because the parents are homosexual, they go to the Regnerus study (2012) as "proof" because it's really the only study conducted that even can be misconstrued to suggest anything resembling evidence. First, I have to say it's ironic that the study is used this way because, even as Regnerus himself admits, his study provides no conclusions regarding the wellbeing of children in families run by same-sex couples. The issues with this study go beyond the fact that this was a study that was funded by a conservative anti-gay organization called the Witherspoon Institute, or that the peer-review process was rushed and poorly implemented. Regnerus' study did not have a sufficient sample size because all but two of the children did not from households initially led by different-sex couples. Those who are anti-gay want to complain about insufficient sample sizes. Is two a woefully small number for a sample size? For sure! And then there's the matter of not having a valid comparison group. You can't take children from unstable, opposite-sex households from "failed heterosexual unions" [that ultimately resulted in family dissolution] because the homosexual partner wanted to keep up the façade of being straight. Much like any of the other studies that have been fallaciously used to discredit same-sex parenting, they do nothing to measure the specific effects of same-sex parenting on the wellbeing of children.
If you're going to make an apples-to-apples comparison, you need the valid comparison group to legitimately make a claim either way (i.e., opposite-sex families with roughly the same means and resources as same-sex couples so we can isolate the sexual orientation of the parents), which is why I was happy to see this very recent study that came out of Australia (Crouch et al., 2014). As far as sample sizes go, it's the largest of any study ever conducted on the topic, not to mention that given the number of same-sex couples in Australia (Crouch et al., p. 1), it's a good representation of the demographic. Not only does this study negate any misconceptions on the anti-gay side, but the study went as far to conclude that even in spite of stigma that the children receive because their parents are homosexual, children of same-sex couples actually fare better. It might have something to do with same-sex parents taking on roles that are suited to their skill sets as opposed to traditional gender stereotypes, but it also might have to do with the fact that since one cannot "knock up the other partner" in homosexual sex, the same-sex couple makes a conscientious decision to have children because they are usually at a point in life where they can handle the responsibilities of childrearing.
Even if you want to argue that Australian cultural norms aren't 100 percent importable or that the study surveyed those who consented, the findings in the Australian study are consistent with years of methodologically sound social science research shows that there is no qualitative difference between same-sex parenting and opposite-sex parenting. If you need more examples of this consensus, then how about a thirty-year longitudinal meta-analysis by the American Academy of Pediatrics (Perrin et al., 2013) or a number of other studies representing the scientific consensus essentially concluding the same thing (e.g., Bos et al., 2014; Farr and Paterson, 2013; Goldberg and Smith, 2013; Lavner et al., 2012; Potter, 2012; Farr et al., 2010; Patterson and Wainwright, 2007; Short et al., 2007; Tasker, 2005)?
What goes into the wellbeing of a child are the relationship between the two parents, the relationship that the parents have with the child, as well as socioeconomic resources. As much as it kills social conservatives (especially those who use the nirvana fallacy only for studies that disagree with their viewpoint), the gender or sexual orientation of the parents are a negligible determinant in the wellbeing of children, especially in comparison to the aforementioned factors. Not only can we see that is the case in these studies, but the anecdotal evidence becomes apparent when people actually meet families with same-sex couples and realize that they function like any other family. It is the sort of compelling nature of the overwhelming evidence that helped the Supreme Court Justice rule 5-4 in United States v. Windsor that DOMA was unconstitutional, and it will continue to be the sort of evidence that will continue convincing people that same-sex couples can parent just as well as opposite-sex couples. What does this mean for the other side? It means that the shaky foundation upon which their arguments were based are crumbling at a faster rate than anticipated, and thusly have one less argument to relegate homosexual individuals to a second-class citizenry. Misconceived arguments based on shaky, tenuous evidence have no place in public policy, and I am glad to see that such arguments have less and less influence in American politics. May this sort of methodology extend to all areas of policy!