Men and women are more prone to different diseases, a new study of the sexes' brains has found.
Scientists from the Netherlands Institute for Brain Research in Amsterdam, found that although doctors already know the two sexes are more likely to have certain disorders, post-mortem and brain imaging studies have now shown that physical differences in the brain mean diseases could be "gender-specific".
The brain's sex is determined when in the womb and it depends on higher levels of the hormones testosterone or oestrogen to become male or female.
Study leader Professor Dick Swaab said because of the difference between the male and female brains, diseases should be looked as either "male or female".
He said there is a different sex ratio for neurological and psychiatric diseases.
"We have shown that sensitive proteins [receptors] for sex hormones are present in the cells that form the stress axis. In women there are more oestrogen receptors and in men more androgen receptors present," he told the BBC.
"That results in higher prevalence of depression in women compared to men because the stress axis is more sensitive," he added.
Other studies into male/female conditions have shown that low levels of testosterone could play a part in multiple sclerosis development and high levels of oestrogen could protect against Parkinson's disease.