STUDY: Married Gay Dads Make the Most Money

A new research paper from the Treasury Department has revealed a significant wage difference between married same-sex and different-sex couples.

Joint tax returns for 2014revealed that the average household earnings of a male same-sex couple is $176,000. Comparatively, this figure is about $52,000 more than a female same-sex couple and $63,000 more than a different-sex couple.

The New York Times points to a number of factors that may account for this wage difference, including the gender pay gap, the cost of child care, and location. Same-sex couples are likelier to live in coastal areas with higher wages -- and a higher cost of living.

The study, which estimated there were 183,280 same-sex marriages in 2014, also revealed differences in where gay couples versus lesbian couples tend to cluster.

In descending order, male same-sex couples are concentrated in San Francisco (3.2 percent), Washington, D.C. (2.7 percent), New York (2.4 percent), Palm Springs, Calif. (1.7 percent), Seattle (1.4 percent), Oakland, Calif. (1.4 percent), Los Angeles (1.1 percent), Long Beach (1 percent), Fort Lauderdale, Fla. (1 percent), and Boston (1 percent).

Female same-sex couples are concentrated in Oakland (2.1 percent), Seattle (1.3 percent), San Francisco (1.1 percent), Springfield, Mass. (1.1 percent), Long Beach, Calif. (1 percent), Washington (0.9 percent), Boston (0.9 percent), Portland, Ore. (0.9 percent), and Madison, Wis. (0.8 percent).

The study also revealed another noteworthy statistic: The demographic with the highest household income is male same-sex couples with children. With an average pretax income of $275,000, these households reported more than twice the earnings of female same-sex couples and different-sex couples. This is likely due to the high cost of surrogacy and adoption, which can be a deterrent to less affluent male same-sex couples seeking to grow their families.

Since the data reported is from 2014, this study likely underrepresents same-sex couples across the United States, which did not have marriage equality nationally until 2015. But as the Times notes, "Maybe the best way to think about these Treasury numbers is as a floor, lower than the hypothetically perfect count of gay marriage but the closest we've ever come to one."