There has been growing interest in the issue of human immunodeficiency virus infection among women, both because of the increasing number of women worldwide infected in recent years (and consequently a higher number of infected children) and because of the higher efficacy of male-to-female transmission of human immunodeficiency virus, which leads to higher risk for women of acquiring the infection compared with men. The present reviews is an attempt to outline the main results obtained from the most recent longitudinal studies conducted among cohorts of human immunodeficiency virus-positive individuals that include analyses of the differences between males and females in the progression of the infection. No evidence of major gender differences between males and females in progression to acquired immune deficiency syndrome or to death is shown by any o the reviewed articles.