'More likely' is having to carry a great deal here.
I don't believe that a strong conclusion has been drawn by Bakker. I think that she has said there may be, but it all requires a lot more research. Without us seeing the results, we also don't know if the grouping were well within the known ranges for each sex.
I think you are trying to convince readers of conclusions that you have strengthened without supporting evidence.
https://www.ese-hormones.org/media/ei0psrhz/transgender-brains-are-more-like-their-desired-gender-from-an-early-age.pdf
Abstract Symposium S30.3
Brain structure and function in gender dysphoria
The concept of gender identity is uniquely human. Hence we are left with the phenomenon of men and women suffering from Gender Dysphoria (GD) also known as transsexualism to study the origins of gender identity in humans. It has been hypothesized that atypical levels of sex steroids during a perinatal critical period of neuronal sexual differentiation may be involved in the development of GD. In order to test this hypothesis, we investigated brain structure and function in individuals diagnosed with GD using magnetic resonance imaging (MRI). Since GD is often diagnosed in childhood and puberty has been proposed to be an additional organizational period in brain differentiation, we included both prepubertal children and adolescents with GD in our studies. First, we measured brain activation upon exposure to androstadienone, a putative male chemo-signal which evokes sex differences in hypothalamic activation (women > men). We found that hypothalamic responses of both adolescent girls and boys diagnosed with GD were more similar to their experienced gender than their birth sex, which supports the hypothesis of a sex-atypical brain differentiation in these individuals. At the structural level, we analyzed both regional gray matter (GM) volumes and white matter (WM) microstructure using diffusion tensor imaging. In cisgender girls, larger GM volumes were observed in the bilateral superior medial frontal and left pre/postcentral cortex, while cis-gender boys had more volume in the bilateral superior-posterior cerebellum and hypothalamus. Within these regions of interest representing sexually dimorphic brain structures, GM volumes of both GD groups deviated from the volumetric characteristics of their birth sex towards those of individuals sharing their gender identity. Furthermore, we found intermediate patterns in WM microstructure in adolescent boys with GD, but only sex-typical ones in adolescent girls with GD. These results on brain structure are thus partially in line with a sex-atypical differentiation of the brain during early development in individuals with GD, but might also suggest that other mechanisms are involved. Indeed, using resting state MRI, we observed GD-specific functional connectivity in the visual network in adolescent girls with GD. The latter is in support of a more recent hypothesis on alterations in brain networks important for own body perception and self-referential processing in individuals with GD.
Abstract below from a follow up that Bakker did in 2023
https://pubmed.ncbi.nlm.nih.gov/39029340/
Abstract
This review has been based on my invited lecture at the annual meeting of the Society for Behavioral Neuroendocrinology in 2023. Gender incongruence is defined as a marked and persistent incongruence between an individual's experienced gender and the sex assigned at birth. A prominent hypothesis on the etiology of gender incongruence proposes that it is related to an altered or less pronounced sexual differentiation of the brain. This hypothesis has primarily been based on postmortem studies of the hypothalamus in transgender individuals. To further address this hypothesis, a series of structural and functional neuroimaging studies were conducted in the Amsterdam cohort of children and adolescents experiencing gender incongruence. Additional research objectives were to determine whether any sex and gender differences are established before or after puberty, as well as whether gender affirming hormone treatment would affect brain development and function. We found some evidence in favor of the sexual differentiation hypothesis at the functional level, but this was less evident at the structural level. We also observed some specific transgender neural signatures, suggesting that they might present a unique brain phenotype rather than being shifted towards either end of the male-female spectrum. Our results further suggest that the years between childhood and mid-adolescence represent an important period in which puberty-related factors influence several neural characteristics, such as white matter development and functional connectivity patterns, in both a sex and gender identity specific way. These latter observations thus lead to the important question about the possible negative consequences of delaying puberty on neurodevelopment. To further address this question, larger-scale, longitudinal studies are required to increase our understanding of the possible neurodevelopmental impacts of delaying puberty in transgender youth.