Pheromones and Gender Identity:Pheromones and Gender Identity:

A pilot study using cerebral electrical activityA pilot study using cerebral electrical activity

Molo Mt, Cappai E, Castelli L, Perozzo P, Tomassoni C, Vighetti S Molo Mt, Cappai E, Castelli L, Perozzo P, Tomassoni C, Vighetti S

CE.R.NE., Fondazione Carlo Molo, Torino, ItalyCE.R.NE., Fondazione Carlo Molo, Torino, Italy

AIM OF THIS STUDYAIM OF THIS STUDY

To examine To examine cerebral electrical activitycerebral electrical activity during the during the nasal administration of male and female nasal administration of male and female pheromonespheromones in transsexuals and eterosexuals, during erotic visual in transsexuals and eterosexuals, during erotic visual stimulationstimulation

The vomeronasal organ (VNO)The vomeronasal organ (VNO)

The vomeronasal organ: The vomeronasal organ: connection with the hypothalamusconnection with the hypothalamus

Subjects:Subjects:–6 heterosexual male–6 heterosexual female–6 male-to-female (MtF) transsexuals

First sessionFirst sessionMtF Estratetraenol/AndrostadienoneMales Estratetraenol/placeboFemales Androstadienone/placebo

Second sessionSecond session–MtF the opposite–Males the opposite–Females the opposite

ResultsResults

A specific software transformed all the A specific software transformed all the numerical valuesnumerical values recorded by each recorded by each electrode into a electrode into a spectrum of coloursspectrum of colours, thus , thus creating a brain map creating a brain map

ProcedureProcedure

MtF Estratetraenol

Males Estratetraenol/placebo

Females Androstadienone/placebo

MtF Androstadienone

Males the opposite

Females the opposite

Results Results 1) In the 1) In the MtF MtF subgroupsubgroup comparing the comparing the Androstadienone Androstadienone to theto the Estratetraenol Estratetraenol condition we found: condition we found:

major decrease in alpha rhythm (p=0.015) major decrease in alpha rhythm (p=0.015) major increase in beta rhythm (p=0.001) major increase in beta rhythm (p=0.001) with with androstadienoneandrostadienone = cerebral arousal = cerebral arousal

MTFMTF

AndrostadienoneAndrostadienone VSVS EstratetraenolEstratetraenol

ProcedureProcedure

MtF Estratetraenol

Males Estratetraenol/placebo

Females Androstadienone/placebo

MtF Androstadienone

Males the opposite

Females the opposite

ResultsResults2) During the 2) During the AndrostadienoneAndrostadienone condition, condition, comparing the comparing the MtF MtF and theand the Female Female subgroupssubgroups we found: we found:

major decrease in alpha rhythm (p=0.045) major decrease in alpha rhythm (p=0.045) major increase in beta rhythm (p=0.045) in major increase in beta rhythm (p=0.045) in the MtF subgroup = cerebral arousalthe MtF subgroup = cerebral arousal

AndrostadienoneAndrostadienone

MtFMtF VS VS Heterosexual females Heterosexual females

ProcedureProcedureMtF Estratetraenol

Males Estratetraenol/placebo

Females Androstadienone/placebo

MtF Androstadienone

Males the opposite

Females the opposite

ResultsResults3) No significant differences were found among the other 3) No significant differences were found among the other conditions:conditions:

• between the MtF and the heterosexual males in the between the MtF and the heterosexual males in the estratetraenol conditionestratetraenol condition•  between the estratetraenol condition and placebo in the between the estratetraenol condition and placebo in the heterosexual males heterosexual males •between the androstadienone condition and placebo in the between the androstadienone condition and placebo in the heterosexual females heterosexual females

ConclusionConclusion

Our study highlights two important findings:Our study highlights two important findings:

1.1. New evidence of biological differences New evidence of biological differences between transsexuals and menbetween transsexuals and men

2.2. Transsexuals are more aroused than Transsexuals are more aroused than heterosexuals by erotic stimuliheterosexuals by erotic stimuli