In 2012, Case and Ramachandran gave a report on the results of a survey of genderfluid people who call themselves bigender who experience involuntary alternation between female and male states. Case and Ramachandran gave this condition the name "Alternating gender incongruity (AGI)." Case and Ramachandran made the hypothesis that gender alternation may reflect an unusual degree (or depth) of hemispheric switching, and the corresponding suppression of sex appropriate body maps in the parietal cortex. They said that "we hypothesize that tracking the nasal cycle, rate of binocular rivalry, and other markers of hemispheric switching will reveal a physiological basis for AGI individuals' subjective reports of gender switches... We base our hypotheses on ancient and modern associations between the left and right hemispheres and the male and female genders." These doctors think that when bigender people feel a change between their gender identities, it might have to do with a change in how they use parts of their brains. The gender change might also have to do with one of the cycles that everyone has in their body, specifically, a valve in the nose that changes sides every two days (the nasal cycle). This is only a hypothesis, meaning that it is an interesting idea that doesn't have proof for now.
- Case, L. K.; Ramachandran, V. S. (2012). "Alternating gender incongruity: A new neuropsychiatric syndrome providing insight into the dynamic plasticity of brain-sex". Medical Hypotheses 78 (5): 626–631. doi:10.1016/j.mehy.2012.01.041. PMID 22364652. https://www.ncbi.nlm.nih.gov/pubmed/22364652
- "Bigender - Boy Today, Girl Tomorrow?". Neuroskeptic. April 8, 2012. http://neuroskeptic.blogspot.com/2012/04/bigender-boy-today-girl-tomorrow.html
- Stix, Gary (2012-04-20). "'Alternating Gender Incongruity' Causes Rapid Shifts Of Gender, Scientist Claims". The Huffington Post. http://www.huffingtonpost.com/2012/04/19/alternating-gender-incongruity_n_1438911.html