Feeds

Lesbians like straight men, researchers find

Why? Asymmetric brain structure

A new approach to endpoint data protection

A study at the Karolinska Institute in Stockholm has provided strong evidence that sexuality is a biologically fixed trait demonstrated in physical brain differences, New Scientist reports.

Specifically, key brain structures in homosexuals which govern "mood, anxiety and aggressiveness" resemble those in heterosexuals of the opposite sex - something likely to have been "forged" in the womb and not the result of later learning processes.

Ivanka Savic and Per Lindström chose to probe these specific brain parameters to avoid the pitfalls of previous studies which, while demonstrating "differences in brain architecture and activity" between gays and straights*, mostly relied on "sexuality-driven cues" which could have been "altered by learning or cognitive processes", as Savic put it.

Savic and Lindström put a group of 90 volunteers through the MRI scanner - 25 heterosexuals and 20 homosexuals of each gender - to determine their overall brain shape and volume. The results showed that straight chaps boasted asymmetric brains, "with the right hemisphere slightly larger", something they shared with lesbians.

Gay men, however, demonstrated symmetrical brains, in common with straight women.

The guinea pigs were then subjected to PET scans to "measure blood flow to the amygdala, part of the brain that governs fear and aggression". The resulting snaps (see below) showed how the amygdala "connected to other parts of the brain, giving clues to how this might influence behaviour".

Amygdala activity in heterosexual men and women (HeM and HeW) and homosexual men and women

Amygdala activity in heterosexual men and women (HeM and HeW) and homosexual men and women (HoM and HoW)

Sure enough, in straight men and lesbians, the amygdala sent signals "mainly into the sensorimotor cortex and the striatum, regions of the brain that trigger the 'fight or flight' response". For gay men and straight women, meanwhile, "the connections were mainly into regions of the brain that manifest fear as intense anxiety".

Savic described the former as "a more action-related response than in women", while noting that in the latter, "regions involved in phobia, anxiety and depression overlap with the pattern we see from the amygdala".

This is significant, Savic noted, because it "fits with data showing that women are three times as likely as men to suffer from mood disorders or depression". Savic added that while homosexual men also suffer higher rates of depression, she cautioned that "it's difficult to know whether this is down to biology, homophobia or simply feelings of being 'different'".

Qazi Rahman, a sexual orientation researcher at London's Queen Mary college, said of the findings: "This study demonstrates that homosexuals of both sexes show strong cross-sex shifts in brain symmetry. The connectivity differences reported in the amygdala are striking."

Savic concluded by admitting it remained to be seen whether the brain differences are "inherited, or result from abnormally high or low exposure in the womb to sex hormones such as testosterone". The research is published in Proceedings of the National Academy of Sciences. ®

Bootnote

*Such as this 1991 report (pdf) investigating differences in the gay and straight male hypothalamus.

The Essential Guide to IT Transformation

More from The Register

next story
Boffins spot weirder quantum capers as neutrons take the high road, spin takes the low
Cheshire cat effect see neutrons and their properties walk different paths
Just TWO climate committee MPs contradict IPCC: The two with SCIENCE degrees
'Greenhouse effect is real, but as for the rest of it ...'
Brit amateur payload set to complete full circle around PLANET EARTH
Ultralight solar radio tracker in glorious 25,000km almost-space odyssey
NASA Mars rover FINALLY equals 1973 Soviet benchmark
Yet to surpass ancient Greek one, however
Famous 'Dish' radio telescope to be emptied in budget crisis: CSIRO
Radio astronomy suffering to protect Square Kilometre Array
BEST BATTERY EVER: All lithium, all the time, plus a dash of carbon nano-stuff
We have found the Holy Grail (of batteries) - boffins
prev story

Whitepapers

7 Elements of Radically Simple OS Migration
Avoid the typical headaches of OS migration during your next project by learning about 7 elements of radically simple OS migration.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Solving today's distributed Big Data backup challenges
Enable IT efficiency and allow a firm to access and reuse corporate information for competitive advantage, ultimately changing business outcomes.
A new approach to endpoint data protection
What is the best way to ensure comprehensive visibility, management, and control of information on both company-owned and employee-owned devices?