Search results
Results From The WOW.Com Content Network
William Byne and colleagues attempted to identify the size differences reported in INAH 1–4 by replicating the experiment using brain sample from other subjects: 14 HIV-positive homosexual males, 34 presumed heterosexual males (10 HIV-positive), and 34 presumed heterosexual females (9 HIV-positive). The researchers found a significant ...
MHC-based sexual selection is known to involve olfactory mechanisms in such vertebrate taxa as fish, mice, humans, primates, birds, and reptiles. [1] At its simplest level, humans have long been acquainted with the sense of olfaction for its use in determining the pleasantness or the unpleasantness of one's resources, food, etc.
Darwin noted that sexual selection is of two kinds and concluded that both kinds had operated on humans: [15] "The sexual struggle is of two kinds; in the one it is between the individuals of the same sex, generally the male sex, in order to drive away or kill their rivals, the females remaining passive; whilst in the other, the struggle is ...
Darwin proposed two explanations for the existence of such traits: these traits are useful in male-male combat or they are preferred by females. [9] This article focuses on the latter. Darwin treated natural selection and sexual selection as two different topics, although in the 1930s biologists defined sexual selection as being a part of ...
Dissection studies found that gay men had significantly smaller sized INAH-3 than heterosexual males, which is shifted in the female typical direction, a finding first demonstrated by neuroscientist Simon LeVay, which has been replicated. [19] Dissection studies are rare, however, due to lack of funding and brain samples. [6]
Studies that established the U=U principle include Opposites Attract, [129] PARTNER 1, [130] PARTNER 2 [5] [131] (which focused on male-male couples), [132] and HPTN052 [133] (which focused on heterosexual couples). [132] These studies involved couples where one partner was HIV-positive and one was HIV-negative, and included regular HIV testing.
Circumcision in sub-Saharan Africa "reduces the acquisition of HIV by heterosexual men by between 38% and 66% over 24 months". [122] Owing to these studies, both the World Health Organization and UNAIDS recommended male circumcision in 2007 as a method of preventing female-to-male HIV transmission in areas with high rates of HIV. [123]
The handicap principle was proposed in 1975 by the Israeli biologist Amotz Zahavi.He argued that mate choice involving what he called "signal selection" would lead to "honest" or reliable signalling between male and female animals, even though they have an interest in bluffing or deceiving each other.