Nature vs. nurture – it’s an age-old consideration when we’re talking about being gay. But a 20-year-old study has some clues – and I think you should know about it for your next dinner-time discussion.

First, let’s make sure we’re on the same page…

On one side, we’ve got the “Nurture” defense. Often cited in the same breath as an anti-gay perspective on the world. And, many times, it’s ironically coupled with a religious element. This seems to be a rare moment in which science and religion are used on the same side of an argument.

(That being said, many gay men often fear the discovery of a “gay gene” because, after all, if we know what causes something, the powers-at-be can figure out how to prevent it from happening in the first place.)

On the other side: Nature. The rally cry for the gay rights movement. It’s the ethical and political defense that creates the foundation for the fight for equality.

While I’m certainly not telling you anything new, I’m here to add a bit of fuel to the fiery conversation: It turns out, you may have your older brother to thank for being gay.

At least that’s what a couple of researchers tested in 1996, creating what has become known as the FBOE – Fraternal Birth Order Effect.

(Yes – it’s an old study, but it’s rarely brought up in the conversations I’ve had recently! And when I’ve mentioned it, people get SHOOK!)

The research found that gay men reported a higher fraternal birth order than their heterosexual counterparts. In other words, the more older brothers you have, the more likely you are to be gay. (In fact, with each older brother, your chances of being gay increase 30%-35%!)

More: Do gay men really need male sex robots?

They also found these results occurred in the womb and not after birth. (A big blow to the nurture defendants out there, huh?)

magic gay spell

Specifically, the FBOE was present even with males who weren’t raised alongside their (biological) brothers; step/adopted brothers had no impact on the sexuality. And furthermore, the FBOE only impacted right-handed guys. (As a south paw, I was disappointed to hear this, too.)

Lastly, and perhaps most significantly, the results spanned across cultures. The FBOE found itself in the United States, Europe, and South America. Giving even more defense to the idea that we all may be “Born This Way” after all.

While one study definitely doesn’t settle the matter, it certainly adds an interesting thought to the chatter, doesn’t it?  So, the next time you find yourself entering this argument with friends and family (or the bigot on Facebook), feel free to impress the crowd with some scientific evidence.

In the meantime, happy debating!