There also seems to a disproportionate amount of male-male lines, weighted just as heavily as male-female lines. I don't think gay marriage is that prevalent to show up with equal weighting, but my cursory googling didn't turn up the number of gay couples in the US.
FTFA: "Same-sex occupation/relationship matchups weren’t common enough to reach the top five in any occupation. So the chart also highlights the top male-male and female-female job matchups for each occupation."
