Lecture 33 Flashcards
What did Roselli and Stormshak show?
Roselli and Stormshak showed that 8% of rams prefer to have sex with other rams than ewes, this is similar to the human % and was tested by giving the ram the chance to mount males or females. In both humans and sheep the hypothalamus controls sexuality. This occurs in the medial preoptic/anterior hypothalamus and controls mate preference, the volume is controlled by exposure to testosterone (male hormone) and estradiol (female hormone), for sheep this is around the time of birth, in humans this is during embryonic development. For straight rams the volume, length and number of neurons is increased compared to ewes and gay rams, density remains the same. Injecting females with testosterone leads to heavy growth of this region. This suggests the region is associated with sexuality and is influenced by hormones.
Why is homosexuality able to spread despite the inability to have genes?
There is a genetic basis for homosexuality. Two reasons for these traits being able to spread are Zietsch et al (the same genes that cause homosexual behaviour also produce some degree of non-stereotypical personality traits, this means when heterosexual they have more sexual partners). Another possible reason is Fecundity (the ability to reproduce) of female relatives of homosexual men is higher than for heterosexual men.
What occured with homophobic and non homophobic individuals in response to videos?
Homophobic men increased in penis circumference more than non homophobic men in response to gay videos. There was no significant difference for lesbian and heterosexual videos.
