A new study has discovered that women have a greater variety of bacteria on their hands than men -- and everybody has more types of bacteria than the researchers expected.

Researchers aren't sure why women harbored a greater variety of bacteria than men; it may have to do with the skin acidity of the skin -- men generally have more acidic skin than women. Other possibilities are differences in sweat and oil gland production between men and women, the frequency of moisturizer or cosmetics applications, skin thickness or hormone production.

Women also may have more bacteria living under the surface of the skin, where they are inaccessible to washing.

The average human hand was shown to harbor 150 species of bacteria.