digital ratio Archives - of Sex and Love

More than fifteen years ago, when I was still in high school, I had heard there was something about your hand shape that could be linked to being gay. I’d heard this repeated throughout the years but always in a way that indicated it was an urban legend, simply a myth. Why did I think this way? Because no one discussed the science; they just held up their hands and explained this fact.

This month’s Science of Sex explains the theories about why hand shape and, specifically, finger length correlates with gay orientations. I hope you enjoy learning a little more about physical and sexual development if you, too, had heard about this phenomenon before and had wondered whether it was true or how.

Science of sex finger length orientation 2d:4d ratio

Researcher Jonathon Manning was the first to notice a correlation between finger length and homosexuality in men. He wrote about how men having a ring finger that’s longer than an index finger (rather than the index finger being longer or both fingers being the same length) can be an indicator of sexual orientation. This high ratio (greater than 1), known as the 2D:4D ratio, is typically more common in women than in men.

But there are a few caveats.

First, we’re talking about the right hand specifically. Secondly, measurements should be taken from the crease to best compare overall finger length. Third, to reiterate, the high ratio is already prevalent in women, so this measurement applies less to them (although, you’ll discover that it does highlight some interesting traits).

This doesn’t mean that you should assume you’re gay if your ring finger is longer, but it might be an indication of biology at play if you don’t identify as straight.

Why does this happen? Researchers know that hormones such as testosterone and estrogen affect our development in the womb. A longer ring finger is connected to the influence of testosterone (a type of androgen) in utero. A lower ratio, which is typical of straight men, corresponds to greater testosterone influence in the womb. The interplay between testosterone and estrogen during this stage is also important.

You might remember that testosterone which encourages skeletal growth. This is why men tend to be taller and have defined Adam’s apples; testosterone spurts during puberty cause this. But finger length is visible at birth, unlike changes that don’t occur until puberty.

Finger length is just one thing that can be affected by hormones in utero. Research suggests, that on average, a gay man’s brain is a bit more feminized than a straight man’s, and that a gay woman’s brain tend to be a bit more masculinized. Of course, there is great variety not just between the sexes but in a single sex, so it is not accurate to say that a game man has the brain of a straight woman. You have to consider the spectrum.

However, there are other ways in which gay men and women are more similar to straight women and men, respectively. Gay men and straight women tend to do better when it comes to verbal measures, and gay men are also more similar to women when it comes to being dependent on landmarks, not direction, when navigation or providing directions. Young gay boys even gravitate toward individual sports rather than team sports.

Higher exam scores, increased neuroticism, better visual recall (in women), and improved literacy also correlates with a greater testosterone influence in utero. There are also some risks from increased testosterone exposure, including an increased risk of prostate cancer as well as lower sperm count, increased risk of heart disease and obesity (in men), and increased risk of mental health conditions such as anxiety, depression, alcohol dependence, and bulimia.

Many of these differences exist even in children; although, some people wonder whether children who are more ‘sex typical’ who later identify as gay may trace their sexual roots more to childhood events than fetal development.

The potential differences and risks I’ve listed above occur to a high 2D:4D ratio. But it’s not just the high ratio that matters. Bisexual men, for instance, have a lower ratio than gay men. Lesbians also tend to have a lower digit ratio, indicating a decreased preference for a masculinized partner, than straight women. However, a high ratio in women correlates to identifying as femme rather than butch.

Amazingly, scientists have been able to study women who were identical twins where one was gay, and the other was not. The differences persist.

A low digit ratio even corresponds with an interest in polygamy.

This research indicates not just the biological differences between gay, straight and bisexual people, but also the significant impact of hormones during our fetal development. The more I read about this, the more I realize that a ton of research supports these theories.

However, I would love to see more research on bisexual men and women specifically — not just because I am one.

Additional Reading