According to statistics, intimate thoughts occur to men many times more often than women. Psychologists decided to investigate the cause of this pattern. It turns out the reason is simple: the sexes react differently to stress.
Scientists have concluded that women always react to stressful situations and various external problems much more acutely. When experiencing stress, they tend to focus their attention entirely on solving their own problems, and therefore thoughts of sex rarely enter their heads at such moments. For men, however, it's a different story: external stimuli don't trigger such a strong reaction, and sexual fantasies often occur to them even when they find themselves in a stressful situation.
Interestingly, experts note the importance of this trend. Had it not developed, humanity would have faced extinction at its earliest stages. In prehistoric times, when great upheavals occurred, pregnant women and mothers with infants were a burden to their fellow tribesmen and often died first. For this reason, women developed a kind of defense mechanism to improve their chances of survival. They simply abstained from sex, postponing childbearing until a more favorable time.
Men, however, reacted completely differently in such situations. They were well aware that not everyone would survive until more peaceful times arrived, and so they tried to leave behind offspring as quickly as possible by impregnating as many women as possible.