Some studies have suggested that the brains of men and women age differently, but there's little consensus as to how they differ. Some researchers found that men's brains were more vulnerable to the effects of age than women. Other studies showed the reverse to be true, and still others found that men and women differ in the types of cognitive decline they experience.

Additionally, some researchers have suggested that diseases such as hypertension, heart disease, and diabetes may be a more critical factor in brain aging than gender.

It has also been suggested that for women, estrogen may have a protective effect on the brain. This has been found to be true in studies with animals. When female rodents were deprived of estrogen, they lost critical connections between neurons in their brains. Studies with humans are now being conducted. It may turn out that hormone replacement therapy for postmenopausal women, which replaces estrogen, may slow down age-related cognitive decline.