Similar to the data on marriage I looked at involving various countries (here), I’ve split the US of A by states, on how they treat same sex unions (with DC and Puerto Rico included also). It's too soon to look at trends but we can look at the current status:
The bar graph shows marriage rates in blue and divorce rates in red, all per capita and all an average of the data I could find (2003 to 2005). The groups are: 1. The average of all states, 2. The average of those with laws and constitutional amendments against equal rights for gay couples, 3. Those with only anti-gay rights laws, no amendments, 4. Those offering civil unions, and 5. Those with full state marriage rights (lonely little Massachusetts). Note that some may define gay couples away from marriage, and yet still offer some civil union recognition, and some states have not acted in this area.
As can be seen, states that have legally acted against marriage for gays do have a slightly greater marriage rate than average. But those with some sort of civil union for gay couples have a significantly higher marriage rate.
While Massachusetts is at the low end of US marriage rates, again, it must be remembered that respect for the institution is not shown in marrying often and divorcing often. As far as having a low divorce rate goes, Massachusetts is #2 in the nation and has been for most of this decade. Utah, with all our politician's talk of family values, is #32 in the nation; most states have lower divorce rates than we do here.
In fact, if you subtract the divorce rate from the marriage rate (the distance from the red to the blue bar), Massachusetts has the same score as the average of all the states. But when all the states that have at least some sort of legal rights for gay unions are averaged together, they have the highest score by far, 32% higher than the anti-gay marriage states. They have more marriages and more marriages that succeed.
Again, what to make of such numbers? It’s too soon, but I’ve heard many claim great confidence in their theories of how rights for our families will mean ruin for marriage. They sometimes claim to have evidence, but, as discussed before, it often falls flat. Here I simply wanted to show their dire if-you-have-it-we’ll-not-want-it predictions and their governments-only-give-gays-marriage-if-the-people-don’t-respect-it theories are not seen in the US data. If anything, it’s the opposite.
Data from the US government’s fedstats.