Testosterone reduces the empathetic responses in Women

Testosterone - Lauded by some and viewed with suspicion by others, few people have a completely neutral view of the hormone that separates boys from girls.

According to the extreme male brain theory of autism, the organising effects of testosterone on the brain in utero, and its ongoing shaping of social behaviors throughout life, explains why men exhibit more aggressive, risk-taking behaviour than women do.

It may also account for the social intelligence deficits of people with autism and the skewed gender ratio of the disorder.

A new study shows that even a little bit of testosterone administered under the tongue can cause a woman to show less empathy — to behave, in other words, more like a man.

This is especially true, researchers say, when a woman has been exposed to higher-than-average levels of testosterone as a fetus.

The 2D:4D Finger Test
One increasingly accepted marker of fetal androgen exposure is the 2D:4D ratio, comparing the length of the index finger to that of the ring finger on the right hand. In women, the ring finger is typically longer than the index finger, whereas in men, or in individuals with high fetal testosterone exposure, the two fingers are of nearly identical length.

Exposure to lower testosterone levels in utero, as inferred by a higher 2D:4D ratio, may protect men from prostate cancer. Researchers have also reported lower 2D:4D ratios in children with autism and in their parents and siblings.

In the study, researchers administered a single 0.5 mg dose of testosterone to 16 young women between 20 and 25 years of age in one session, and a single dose of placebo in a second session 48 hours later. The women experienced a ten-fold increase in blood testosterone levels 15 minutes after intake, with the levels returning to baseline in about an hour and a half.

During that time, the participants took a test of cognitive empathy called Reading the Mind in the Eyes, which asks them to infer the emotions expressed in a photograph of a pair of eyes. Interestingly, 75 percent of the women in the study achieved lower scores on the test after testosterone than after placebo.

When the researchers compared the women's 2D:4D ratios, as computed from scans of their right hands, they found something even more interesting: the women with the lowest 2D:4D ratios (highest fetal testosterone exposure) showed the most significant decrease in empathy as measured by the test.

This may not be not a slam-dunk for the extreme male brain theory, but the results jibe with other studies that have found a continuum of social cognition abilities.

Estrogen, Puberty and Autism | Neurodiversity

Estrogen, Puberty and Autism Neurodiversity

To what degree have high and low-fat diets influenced human evolution? If low fat delays puberty and results in more brain growth, might this be because more synapses are useful for finding more fat?

When there is more fat in diets and puberty rates drop, for a woman there is a greater number of children produced over a single lifetime. Less fat in diet, fewer children produced. This seems like an evolutionary process.

Do thin males with less fat have less estrogen, reach puberty later, have bigger brains and exhibit more neotenous features?

Should autistic males be on extremely low-fat diets so that they reach puberty later, thus allowing more time for their brains to mature?

Is the degree of brain synapse pruning that occurs in infancy related to the estrogen levels in the mother or the child? High mother testosterone levels encourage higher rates of autism, which may be directly related to less pervasive synapse pruning. Is it possible that a high mother estrogen level results in low male baby estrogen levels that prolong or diminish the testosterone prunings?

In other words, the Simon Baron-Cohen research regarding mother testosterone levels and autism may be related to mother estrogen levels. If low estrogen at puberty translates to delayed puberty, delayed testosterone surges and increased brain growth, then the same process may be engaged during the first testosterone surges that compel a diminution of the right cerebral hemisphere during infancy. Low estrogen levels as an embryo, infant and toddler may have a direct impact on cerebral lateralization and synapse production.

Another interesting article 'Introduction to Neotenty' Here ............