Biology and sexual orientation INAH3 weight for the heterosexual male brains was significantly larger than for the heterosexual female brains, while the results for the gay male group were between those of the other two groups but not quite significantly different from either. The neuron count also found a male-female difference in INAH3, but found no trend related to sexual orientation. A 2010 study, Garcia-Falgueras and Swaab asserted that "the fetal brain develops during the intrauterine period in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge.
Transgender hormone therapy (male-to-female) the gender they identify with. Introducing exogenous hormones into the body impacts it at every level and many patients report changes in energy levels, mood, appetite, etc. The goal of the therapy, and indeed all somatic treatments, is to provide patients with a more satisfying body that is more congruent with their gender identity. Some medical conditions may be a reason to withhold hormone replacement therapy because of the harm it could cause to the patient. Such interfering factors are described in medicine as contraindications. Absolute contraindications – those that can cause life-threatening complications, and in which hormone replacement therapy