Men's aggressive reaction to stress all down to a single gene, scientists say

It is a common scenario around the world. After a few too many at the local bar, a woman has to call on her skills of diplomacy as she tries to diffuse male-dominated aggression.

Now Australian scientists believe they have found the single gene responsible for making men more aggressive than women during stressful situations.

Scientists believe the SRY gene, which controls male development and is only found in men, may also promote aggression and other typically male behavioral traits, MedicalXpress reported.

The study -- published in BioEssays -- found the sex-determining gene "exerts maleness" by directly acting on the brain and could explain why men are typically more macho than women.

Previously, studies have mostly focused on men and their reactions during stress and not on the differences between the sexes.

"Historically males and females have been under different selection pressures which are reflected by biochemical and behavioral differences between the sexes," said Dr. Joohyung Lee, from Prince Henry's Institute in Melbourne.

"The aggressive fight-or-flight reaction is more dominant in men, while women predominantly adopt a less aggressive tend-and-befriend response.

"Besides the testes, SRY protein is present in a number of vital organs in the male body, including the heart, lungs and brain, indicating it has a role beyond early sex determination.

"This suggests SRY exerts male-specific effects in tissues outside the testis, such as regulating cardiovascular function and neural activity, both of which play a vital role in our response to stress."

Lee and study co-author Professor Vincent Harley believe the SRY gene stimulates organs in men's bodies to deal with stress through increased release of catecholamine and blood flow to organs.

This also bolsters aggression and increased movement which stimulate fight-or-flight reactions in men. For women, estrogen and internal pain-fighting chemicals may help therm have a calmer reaction to difficult situations.

Click here to read more from Medical Express.