The stereotypic and oversimplified relationship between female sex hormones and
undesirable behavior dates to the earliest days of human society, as already the
ancient Greek word for the uterus, “hystera” indicated an
aversive connection. Remaining and evolving throughout the centuries,
transcending across cultures and various aspects of everyday life, its
perception was only recently reframed. Contemporarily, the complex interaction
of hormonal phases (i. e., the menstrual cycle), hormonal medication
(i. e., oral contraceptives), women’s psychological well-being,
and behavior is the subject of multifaceted and more reflected discussions. A
driving force of this ongoing paradigm shift was the introduction of this highly
interesting and important topic into the realm of scientific research. This
refers to neuroscientific research as it enables a multimodal approach combining
aspects of physiology, medicine, and psychology. Here a growing body of
literature points towards significant alterations of both brain function, such
as lateralization of cognitive functions, and structure, such as gray matter
concentrations, due to fluctuations and changes in hormonal levels. This
especially concerns female sex hormones. However, the more research is conducted
within this field, the less reliable these observations and derived insights
appear. This may be due to two particular factors: measurement inconsistencies
and diverse hormonal phases accompanied by interindividual differences. The
first factor refers to the prominent unreliability of one of the primarily
utilized neuroscientific research instruments: functional magnetic resonance
imaging (fMRI). This unreliability is seemingly present in paradigms and
analyses, and their interplay, and is additionally affected by the second
factor. In more detail, hormonal phases and levels further influence
neuroscientific results obtained through fMRI as outcomes vary drastically
across different cycle phases and medication. This resulting vast uncertainty
thus tremendously hinders the further advancement of our understanding of how
female sex hormones might alter brain structure and function and, ultimately,
behavior.This review summarizes parts of the current state of research and outlines the
essential requirements to further investigate and understand the female
brain’s underlying physiological and anatomical features.