Autistic features in girls from a psychiatric sample are strongly associated with a low 2D:4D ratio

A low 2D:4D ratio in girls was highly predictive of the presence of autistic features. Thus, a low ratio could possibly be used as a diagnostic predictor in clinical practice.

Edge.org - Sex At Your Fingertips
Simon Baron - Cohen : Psychologist, Autism Research Centre, Cambridge University; Author, Zero Degrees of...

Foetal testosterone is tricky to get your hands on, since the last thing a scientist wants to do is interfere with the delicate homeostasis of the uterine environment. In recent years a proxy for foetal testosterone has been proposed: the ratio between the second and fourth finger digit lengths (or 2D:4D ratio). Males have a lower ratio than females in the population, and this is held to be set during foetal life and remains stable throughout one's life. So scientists no longer have to think of imaginative ways to measure the testosterone levels directly in the womb. They can simply take a xerox of someone's hand, palm down, at any time in their life, to measure a proxy for levels of testosterone in the womb.

I was skeptical of the 2D:4D measure for a long time, simply because it made little sense that how long your 2nd and 4th fingers were should have anything to do with your hormones prenatally. But just last year, in Proceedings of the National Academy of Sciences, Zheng and Cohn showed how even in mice paws, the density of receptors for testosterone and oestrogen varies in the 2nd and 4th digits, making another beautiful explanation for why your finger ratio length is directly affected by these hormones. That same hormone that masculinizes your brain is at work at your fingertips.

Could Giftedness Be Linked to Prenatal Exposure of Higher Levels of Hormones?

ScienceDaily (Mar. 11, 2011) — A longstanding debate as to whether genius is a byproduct of good genes or good environment has an upstart challenger that may take the discussion in an entirely new direction. University of Alberta researcher Marty Mrazik says being bright may be due to an excess level of a natural hormone.

Mrazik, a professor in the Faculty of Education's educational psychology department, and a colleague from Rider University in the U.S., have published a paper in Roeper Review linking giftedness (having an IQ score of 130 or higher) to prenatal exposure of higher levels of testosterone. Mrazik hypothesizes that, in the same way that physical and cognitive deficiencies can be developed in utero, so, too, could similar exposure to this naturally occurring chemical result in giftedness.

More prenatal testosterone makes 'masculine' boys
by Daniel Cossins, Wednesday, 15 February 2012

PHILADELPHIA: The link between prenatal hormone exposure and the facial features we associate with masculinity and dominance in adult men can be observed in early childhood.

Scientists have known that 'masculine' facial characteristics are linked to high levels of prenatal testosterone, and this can be predicted by finger lengths. But a study published in Proceedings of the Royal Society B today has shown that this is expressed in boys before the onset of puberty, which is earlier than previously thought.

Several studies have revealed that people who were exposed to high levels of prenatal testosterone - as indicated by a low second-to-fourth digit ratio (2D:4D) or the relative length of index to the ring finger - end up with a more 'masculine' face. That means they have a wider jaw, thicker eyebrows, a wider and shorter nose and a shorter forehead: characteristics found to be associated with masculinity and dominance among adults.

DFG Science TV - Masculine, More Masculine, the Most Masculine
Love à la Darwin: Episode 07, 14/12/2009

Are men really more daring than women and what has that got to do with the ring finger?

kattkvinna skrev:He, he, snart kanske man börjar mäta händer och fingrar på barn och på vuxna vid misstanke om ASD.

Autistic features in girls from a psychiatric sample are strongly associated with a low 2D:4D ratio

A low 2D:4D ratio in girls was highly predictive of the presence of autistic features. Thus, a low ratio could possibly be used as a diagnostic predictor in clinical practice.

Lägre testosteronnivåer ökar risken för hjärtsjukdom
NYHET: 2011-10-07

Män med låga nivåer av det manliga könshormonet testosteron löper en ökad risk att drabbas av hjärtsjukdom. Det visar forskare vid Sahlgrenska akademin, som i en internationell studie på 14 000 män också hittat generna som styr risken att få låga testosteronnivåer.

Det manliga könshormonet testosteron är inblandat i en rad viktiga kroppsliga funktioner som könsdriften och immunförsvaret, och styr utvecklandet av manliga karaktärsdrag som aggression, djupare röst och mer muskelmassa.