In reality, of course, it shouldn’t matter what other people think. But as a measure of social change, the Gallup organization has once again uncovered another shift in Americans’ thinking. It’s intriguing despite that unbelievably boring sociology professor I had quite a few years ago.

Back in 1977 when Gallup first asked why people thought gays were gay and lesbians were lesbians — otherwise known as “nature vs nurture” — a substantial majority of Americans knew it was their upbringing and environment. Back then, 56 percent said that and only 13 percent said it was a birth trait.

That thinking didn’t change much until the last decade of the 20th century. But by the middle of Bill Clinton’s two terms, Gallup was detecting a dramatic shift. In 1996, the birth belief had jumped to 31 percent and by George W. Bush’s inauguration in 2001 it had climbed to 40 percent.

Now, according to Gallup’s latest pulse-taking, fully half of Americans have bought into the birth belief, while the environment crowd has dwindled to 30 percent. Ten percent attribute both causes while six percent just don’t know.

The growth in the birth believers has come across all political and demographic groups. But over time it is most pronounced among college graduates, younger people (18 to 34), Democrats, other left-leaners and non-churchgoers. It’s also moving among conservatives, Republicans and churchgoers, but less so.

The shifts parallel a similar social movement regarding same-sex marriage. Today, a new high — more than two-thirds (67 percent) — favor same-sex marriages being legal, which is helpful if immaterial because the Supreme Court has already ruled that.

Gallup also recently found the percentage of Americans identifying as bisexual, gay, lesbian or transgender has increased to 4.5 percent, a one point jump since 2012. Of course, that could also represent simply more feeling comfortable publicly acknowledging their orientation rather han an actual increase.