Health and medicine , Education and society , Doctoral. Hormonal environments in the womb may help explain the evolutionary origins of female homosexuality and determine the spectrum of sexual orientation in women according to a review article published in the Archives of Sexual Behavior. An international research team that includes Severi Luoto, doctoral candidate in evolutionary psychology from the University of Auckland, propose that the degree to which male-typical and female-typical traits vary between women is based on the degree and type of sex hormone exposure in prenatal development. Rantala from University of Turku in Finland and Professor Indrikis Krams from the University of Tartu in Estonia and University of Latvia, examined scientific studies from neuroscience, biology and psychology. Their review identified clusters of sex-typical traits which vary in degrees of masculinity. Non-heterosexual women tend toward higher masculinity on physiological traits such as facial structure, digit ratio, long bone growth and auditory biomarkers.
Testosterone and sex role identification in lesbian couples
Origins of female homosexuality - The University of Auckland
Among lesbian couples expecting their first child, low prenatal testosterone levels predict a higher quality of nuturing behavior, according to a new University of Michigan study. People tend to associate the hormone testosterone with males, competition and dominance. But women also have testosterone and it is also associated with caregiving and nurturance. Twenty-five lesbian couples between ages 18 and 45 provided saliva samples to measure testosterone each trimester during pregnancy and completed a questionnaire three months after their scheduled due date. The questionnaire assessed spousal support, division of household labor and infant care, parenting behaviors and relationship quality. Chin and colleagues found that—for both partners—lower testosterone during pregnancy predicted better relationship quality and more time spent taking care of the baby.