Male hormones, particularly testosterone, are the aggression hormones that cause men to hunt and kill prey.
The results show that testosterone and estrogen have opposite effects on a gene nicknamed RORA.
But after puberty boys catch up and excel in mathematical reasoning as testosterone boosts their spatial ability.
Levels of free testosterone found in the 300-microgram-dose group were close to those usually seen in women ages 18 to 24 years.
The testosterone in some animals, such as spotted hyenas, is so high that they are born with a full set of teeth and are so aggressive that the young often eat each other.
Or if this test led to some kind of prenatal treatment, such as the use of drugs to block the effect of testosterone which is already medically possible, would this be desirable?
Because having a kid appears to cut testosterone levels-essentially priming men to be better dads.
Other terms for so-called male menopause include testosterone deficiency, androgen deficiency of the aging male and late-onset hypogonadism.
When a cell has high levels of testosterone, RORA levels run low, which affects every gene that RORA is supposed to turn on.
So far, in early tests, the agent worked on 95% of the men who tried it, but there are lingering questions about the long-term effects of suppressing testosterone in men.
It raises testosterone levels by roughly 20% and lowers the stress hormone cortisol by the same.
He said: "Our findings show an association between high testosterone and risk-taking among males in three domains: recreational, social and financial."
Creatures with the highest testosterone levels rule the animal kingdom.
Hu said her new study adds to that work by proposing a mechanism linking testosterone with autistic behaviors.
Professor Jack van Honk, one of the researchers, said: "We are excited by this finding because it suggests testosterone levels prenatally prime later testosterone effects on the mind."
The downside of testosterone for modern males is that unless it is allowed to vent itself in a physical outlet, it may create aggression and can cause anti - social problems.
Men's faces are shaped by testosterone, which helps develop a larger lower face and jaw and a prominent brow.
Still, violent crime is largely perpetrated by young men and high testosterone is a factor in their reckless conduct that we ignore at our peril.
